Understanding Conductivity Factor (CF) in Hydroponics

Many new hydroponic gardeners get confused with all the readings they need to take. With EC, pH and TDS, it can be boggling. To make it worse, there is another reading growers should be aware of.

CF and how to control it is can be daunting, luckily though, these readings are not so hard to fully understand.

Here, we will explain what CF is and how it can affect your garden. We will also see how it relates to other readings you need to take from your solutions

What is CF?

CF stands for conductivity factor, and like the EC of your nutrient mix, it is a way of telling you how weak or strong your formulation is.

If it is too strong, you can quickly overfeed your crops, and if it is, too weak and you can find your plants are suffering nutrient deficiencies.

To make things even simpler for new growers, the CF (Conductivity factor) and the EC (Electrical Conductivity) are basically the same thing.

There is one slight difference, and that is CF is a 10 x multiple of an EC reading. You may wonder why there is a need for another reading, which is the same as another albeit in a different format.

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It is true; a CF reading is just your EC reading and multiplied by 10. It can be used because it eliminates any requirement for a decimal point.

To simplify this, you can use the following:

  • 1 EC equals 10 CF
  • EC multiplied by 10 equals your CF
  • CF divided by 10 equals your EC

Understanding Your Target CF

When you purchase any hydroponic nutrients, you will find that the majority of suppliers give a target EC or CF. this will of course though assume that you are setting out with an EC/ CF of zero.

About your water, this can only come from pure water, which has a CF/ EC of zero. Water from the faucet contains minerals, and will vary depending on if it is soft water, or it is hard water as you can see here.

Soft Water – is generally CF 2 (or EC of 0.2)

Hard Water – is generally CF 8 (or EC 0.8)

There are two steps to find out your actual target CF.

  1. Take a reading of your base water to find the CF
  2. Add this reading to your manufacturers target CF

As an example, if you have water from your faucet, and it is soft water. You will have a CF of 2. If your nutrient manufacturers target CF is 16, you will have an actual target CF of 18.

When manufacturers offer these target CF’s, they will do so for plants that are at various stages of growth.

  • Young plants – CF of between 4 to 10
  • Established plants – CF of between 10 to 18

Just like EC readings, an ideal CF will vary. The CF can be seen as your nutrient to water ratio. This means if plants are hungry, they will require more nutrients, and likewise, if they are thirsty, they will take up more water.

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Just like other readings in hydroponics, there can be many factors, which affect things. With this, there are many things that can make crops and plants thirstier or hungrier throughout their life.

  • Types and size of crops and plants
  • Season and temperature of grow room
  • Water hardness used
  • Method of growing

Taking a reading may not deliver the chance to find an exact CF. It is for a reason that you will need to take readings at regular intervals.

Just like your pH levels, you will find your CF levels go up or down, and you will need to respond to bring these back in line.

Checking Your CF

To test your CF in your solution can be much the same as taking any other reading. There are various meters, which can take readings of CF along with EC, pH and others. Most of these require manual calibration in comparison to one device called the Truncheon by Bluelab.

These are factory calibrated, but they do come with a higher price tag than the other digital meters.

  1. Leave a pale/ bucket of water from the faucet outside to dechlorinate for at least 24-hours.
  2. Use your CF meter to take a background reading
  3. Add your nutrients at the manufacturers recommended doses
  4. Once they have dissolved and settled, take another reading
  5. If it is too high, add water to lower the CF level

One thing that is worth remembering is that a one-degree rise in temperature can raise your CF reading by 2%. Because of this, you should aim to take your readings at the same time every day.

Correcting CF Levels

Ideally, you will want your CF levels to remain the same as your plants feed. If this happens, it means you have your CF set correctly.

However, in the instances, it has gone up or down, the first thing not to do is panic; you can adjust this as required.

When CF levels rise, this means plants are taking up more water than you expected them to. This can happen when the environment is warmer, and plants become thirstier. This will leave the concentration of TDS increasing in strength.

To lower this, you should top off your tank with plain water only. This is the standard way of making sure your plants don’t suffer from nutrient burn.

If your CF levels drop, many growers will advise in adding more nutrients to raise these levels. However, there are more growers who advise to never add nutrients at this stage. It is better to let plants have access to less than to begin over feeding them.

If you want to be sure they get enough nutrients, the easiest way can be to flush your tank and add a new batch of nutrients with the correct CF.

Warning Signs Your CF Levels are Wrong

The signs that levels are not correct are very similar to EC levels that are out of balance.

If you are underfeeding, you may see

  • Phosphorous: Stems and parts of large leaves begin to purple
  • Nitrogen: Leaf tips yellow and begin moving toward the step of the plant
  • Potassium: The yellowing moves from the tips toward the main leaf veins

If you find out you are over feeding, you may spot the following signs

  • Your plants leaves begin curling downward
  • Leaves have stunted growth and are too small
  • Leaves are dark and lack any vibrancy


There may be a good many growers who find out that CF isn’t used very often when taking readings of their solutions. It is however better to understand what it is, and how to calculate it if needed.

It is good to know that one CF is equivalent to around 65 PPM (Parts per million), and the EC with be around 650 PPM as an equivalent. Because there are lots of confusion with these figures, new growers follow the simplest of methods, which works for thousands of gardeners with hydroponic systems.

Keep things simple and run half-strength solutions in the vegetative stage of growth. Once your plants reach the fruiting and flowering phases, you can then deliver a full strength set of nutrients when they can handle them.

Aside from this, flush your tank and replenish with new nutrients on a regular basis, and you will see great results.

Associated Questions

Why is a CF/ EC level important? While some growers don’t use these readings, knowing what they mean does allow you to understand more what happens in your system. Your CF and EC can stay the same, or go up and down. If plants are taking up water, then you should always see a CF that increases as nutrient concentrations increase.

What does PPM mean? Parts per Million means one part of your nutrients in one million parts of your solution.

Which is the best meter, an EC or TDS meter? Many new meters can read multiple things and will make the conversions for you. However, it does depend on your plant nutrient recommendations. If your scales are in EC/ CF then a meter which reads these, is ideal, however, if you are using PPM, then a sodium chloride TDS meter will be easier to use.

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4 Common Hydroponic Plant Problems (With Solutions)

It doesn’t matter how experienced a hydroponic grower is, there can be many occasions when they have plant problems and they need fixing. This is worse for new gardeners because they may never have faced these issues and wonder how they can fix them.

Here we will look at some of the more common problems, which occur with plants, and how growers can set about tackling them. What are the most common hydroponic plant problems? Some of the most common problems come from diseases, pests, grower mistakes and problems with the system environment.

Growers are tasked with making sure their plants have the exact amounts nutrients, water and light. This goes a long way to make sure there are no deficiencies yet it can still happen without a grower knowing. All of these factors play a very important role, and a grower doing something in response to another action can have a reaction in a very different area.

We will now look at the key problem areas in plants and how you can go about resolving these.

Hydroponic Plant Diseases

One of the more frightening problems growers face is plant disease. They may think there is little hope and in their mind, they are more than likely thinking of tossing out their entire crop.

In some cases, this may be the case, yet this is in the extreme times. Most times, there is something growers can do to resolve the plant disease issue and save their plants.

A grower should already understand, a growing room needs to be a sterile environment, and even entering it in dirty clothes can be enough to trigger some of these diseases. The same goes for necrotic plant tissue that stays in a system. This dead tissue rots and is the ideal starting place for deadly bacteria and pathogens.

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Here are the primary plant diseases growers need to be wary of:

Powdery Mildew – This stunts plant growth and reduces yields considerably. Once it gets into a garden, it can be a struggle to prevent it from spreading. When you see this, leaves will be covered in white blotches as if someone has dusted them in white powder. Two key factors allow this to infect plants, first is the strength of the plant, and second, the environment.

The best speedy solution to fix this is remove infected leaves, and ensure there is lots of airflow and lower the levels of humidity. Plants, which grow stronger, have thicker cell walls, and it is this, which prevents powdery mildew from sending down its feeding tubes. You can also rinse the spores off the leaves, but give your plants the best chance of drying afterward.

Downy Mildew – This kind of mildew is found more on agricultural plants rather than the powdery variety, which is found on flowering plants most often. The tops of the leaves will be covered in yellow patches; while underneath there will be a fain frosting of gray, violet or blue. To stop this, you will go through the same as above such as pruning infected leaves and tissue, and making sure plants have lots of room for good airflow.

Steps to Prevent Plant Disease

Prevention is the best cure for plant disease. Even with these, a grower can face many more such as Gray mold and other varieties.

There are a few things you can do to make sure your plants stay clean and healthy.

Clean Clothes – It can be easy for disease to travel around on your clothes. Spores are microscopic, and can latch onto anything before falling toward their prey when they feel the time is right. Grow rooms should be sterile, and the best way to begin this practice is wear clothes which are somewhat clean and haven’t been used for working in the outdoor garden.

Keep a Clean Grow Room – There are many different molds and mildews, we have only touched on a couple, yet they can all find their way into your grow room. Keeping a clean area is vital as is making sure any ventilation is properly filtered, and there is not dirty or dead plant debris laying around. Any tools need wiping down at regular intervals, and there should be no sign of soil anywhere inside your growing area.

Algae Plant Problems in Hydroponics

Because the spores of algae are microscopic, they can enter your grow room in the same way as the spores that lead to plant disease. However, in hydroponics, the conditions are perfect for algae growth because they are so similar to plants.

There are a number of growers who say to starve algae of what is feeding it, yet doing this means you will be starving your plants of the goodness they require.

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It is more a case of what are the degrees of algae in a system? This will determine the level of plant problems growers’ face. If you catch algae growth early enough, it won’t be as big a problem, yet the longer it goes on, more significant factors take place.

First, there is a drop in nutrient levels as the algae uses these for its own growth; second, the amount of dissolved oxygen is reduced. From here, you can have plants suffocating and then there will be the onset of root rot.

Preventing Algae in Hydroponics

Preventing algae can be an ongoing saga, and it will mean keeping your growing area as clean as possible. Algae doesn’t like dry surfaces, so this is why you only see it around the water line in your system. Commercial algaecides are of little use, and there is no better way of ridding a system than flushing it and giving a good clean.

It is best to do this when you are changing your batch of nutrients, because you will then know your system is as clean as it can be.

To do this, drain your system of liquid. You can then use hydrogen peroxide at a ratio of 3 milliliters per gallon of water. Before topping your system with this solution, check for debris and remove this. Top your system above your regular water line and run this peroxide solution for up to six hours without plants. Drain and rinse then drain again, and wipe down every surface you can reach.

Two ways to slow the growth of algae is to use opaque materials on your system. Light is one thing that algae loves as it tries to grow in your tank. Second is to cover any exposed water. This is to slow the algae from entering your system as well as blocking out light.

One other tip is to use a UVC light in your filtration system. These can be costly, yet they can kill microorganisms. A more natural way is to administer up to 10 drops of grapefruit seed extract per gallon of water, these low doses don’t harm plants, yet they are effective at fending off algae.

Hydroponic Plant Problems from Pests

There are many who think that hydroponic gardens are free from pests however this isn’t the case. While they are free from some, it is nearly impossible to keep pests from an environment that is as warm as an indoor growing area.

Plant pests are unfortunately developed to travel between crops even if these are indoors. Growers do need to be vigilant because an infestation of pests can quickly ruin crops before they are aware of the problem.

Here are some of the more common indoor garden pests growers can encounter.

Spider Mites– Spider Mites are probably the most common of all the indoor garden pests. Because the mites are so small, you probably won’t notice them into its too late. There are two very easy ways that you can spot spider mites. One way is to keep an eye out for a webbing material that kind of looks as if it came from a spider. The second way is to wipe the back of the leaves with a cloth and see if there are any traces of the bugs on it.

Thrips- Thrips are a hard pest to identify, but with a good eye, you will notice small black speck on your plant’s leaves. The leaves will usually turn brown in color and become dried out.

Aphids– Another name for these pests is plant lice. They will be either green or black in color. The aphids will severely weaken your plants by sucking all of the juices out of them. This will cause your leaves to turn yellow and then brown. They are mostly located on the stem.

Whiteflies– They resemble small moths that are all white in color. Their color makes them very easy to find, but they can fly, so they are very hard to catch.

Fungus Gnats- Although the adults of this species aren’t harmful, the larva form can be very deadly for your plants. These pests can slow down the growth of your plants by feeding on the roots. These appear to be small white worms in the growing media.

Plant Pest Prevention Methods

Although there are many technologies for the prevention of pests, some of the better ones are still the older natural ones. One of the favorites of growers is the compound neem oil. This has been used for centuries, but has only been available in the past few years in an easy form for application.

Neem is also a longer-term approach because it is an insect growth regulator. This means it will work better over the long-term to break the life cycle of the insects. The one good thing with neem is that as it is a plant extract, it is nontoxic in smaller doses, yet care does need to be taken.

Sticky Traps are another great means of controlling these pests. When you hang sticky traps around the room, you can trap the pests, and this will make it easy to identify them. Blue stick cards are good for catching thrips. Yellow cards attract fungus gnats and whiteflies. It is important that you make sure some cards are at the soil level and the medium level of your plants.

Another natural means of protecting plants against these pests is the introduction of beneficial pests. Outdoor gardeners know all too well about these and they can also work for indoor gardens.

Ladybugs are a prime example, as are lacewings, preying mates while there are also Hypoaspis and Encarsia Formosa, which eat greenhouse whiteflies, fungus gnats and springtails. The problem using these in some gardens is that they themselves struggle to survive over long periods.

Nutrient Deficiency Plant Problems in Hydroponics

New growers may think there are many plant problems such as the above, yet the one thing they are delivering to their plants can be one of the major areas where there are plant issues.

Either delivering too many nutrients or not enough can lead to nutrient deficiencies. This can leave gardeners frustrated, as they are not sure what is causing their crops to suffer. Symptoms can be saying one thing while the cause is actually from something else.

Nutrient Lockout can come from many areas in a system. Water can be a culprit especially if pH levels are out of the ideal range. It is vital for growers to know the ranges that are suitable for good plant growth and the things that can affect this. Faucet water can have a bearing on pH, as there are many compounds in this water depending on the region you live.

Heat stress can also lead to nutrient deficiencies as can an insufficient amount of lighting.

Growers need to know how to diagnose deficiencies before they can fix the issues. Leaves should be an even color all the way across and they should have a uniform shape. Once leaves begin showing a shape, which is not the same as older foliage, or the colors are patchy then these are the first signs there is a problem.

There are many signs of nutrient deficiency yet most come from the macronutrients because they are the ones plants use the most of. To fix and prevent these is not as hard as it appears if they are caught soon enough.

Fixing Nutrient Deficiency Plant Problems in Hydroponics

Two of the main areas growers need to attend to when fixing these issues are the pH levels. It is vital to monitor these levels daily, as it is to measure the EC levels of the solution. This is straightforward with a good digital EC tester, and a pH testing device.

Growers should also understand that just because a plant is showing signs of a nutrient deficiency, it doesn’t mean their solution is lacking this nutrient. Phosphorous levels, which are too high, can block plants taking up other nutrients.

An iron deficiency can be something as simple as a nutrient solution being colder than the recommended temperature. The range of temperatures for a solution should be around 68 and 72 degrees Fahrenheit. Iron deficiencies can also be caused by a solution, which is rich in manganese. This shows why adding more nutrients isn’t necessarily the best approach.

The best approach for fixing any nutrient deficiency can be to flush the system. It may sound counterproductive to take all the nutrients away from the plants, yet in almost every cases, the solution doesn’t lack the nutrients and the deficiency is caused by a secondary factor.

To do this, remove any leaves that are showing large signs of discoloration or they are badly damaged. In severe cases, you may need to go back as far as the stem. Removing any leaf matter that may die is vital because if this rots, it allows pathogens to enter the system.

Pots and growing medium should be flushed with pH-balanced water to remove any salt buildup, and then the system should be topped up with fresh water only. At this stage, it should be run for a period of 24-hours before measuring pH and EC levels again.

Once both levels are back in line, you can mix a new batch, yet it is advisable to only use a three quarter strength of the manufacturer’s dosage. One final addition can be some organic liquid tea as a supplement. This is beneficial to your plants without increasing certain nutrients to the point of causing lockout.


Growers do have many things to contend with, and in some instances, they may wonder if it is worth having a hydroponic garden because of these problems.

While these can hit at any time, once the right precautions are in place, the actual chances of these problems hitting a garden are dramatically reduced. Growers quickly understand how their systems and gardens work, so they will be taking precautionary measures as a matter of course.

A hydroponic garden is worth the extra effort it takes to control these problems, because if it weren’t the number of growers would be declining rather than increasing.

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9 Vegetables You Can Grow In Hydroponics (with pictures)

Hydroponics is a booming means of growing produce at home. New gardeners who are thinking about this often wonder what are the best crops to grow, which are easy and will deliver the best yields.

There are many reasons why individuals are turning to this way of growing, and it doesn’t matter if it is because they want to help save the planet, or cut down on their grocery bill. Hydroponics is a great way to do this and much more.

While not every vegetable thrives in a hydroponic environment, many do. So here are the top, nine any new hydroponic grower can grow into their system. Some are very easy, while others take a bit more effort and space, but nonetheless, all of them are worth adding to any hydroponic garden.

Here, we will look at each of these top nine hydroponic vegetables and which systems are best suited to their growth.

Best Vegetables for Hydroponics 


Leaf lettuce makes an outstanding option for hydroponic cultivation. It grows in the simplest systems and requires minimal attention. As you grow, you can harvest the external leaves from your lettuce, meaning you will end with a prolonged crop of fresh, crunchy lettuce. As the leaves are cut, the internal leaves will grow rapidly to take their place.

There are many varieties to choose from, and most of them are suitable for growing this way. The more common types are:

  • Tom Thumb
  • Boston
  • Iceberg
  • New York
  • Romaine
  • Buttercrunch Bibb
  • Simpson
  • Waldman’s Dark Green
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Lettuce are suitable to grow in NFT, DWC and Ebb and Flow systems. If the temperature gets too hot for them, lettuce can bolt and may taste bitter. They are a cool weather vegetable and like temperatures between 50 and 70 degrees fahrenheit. Lettuce are also fond of high nitrogen levels.


Kale is one of the top vegetables that is grown because of its health benefits and is delicious flavor. This can be germinated from seeds and once it begins growing, it can handle a wide range of temperatures from 45 to 85 degrees fahrenheit.

From seed to harvest takes around ten weeks, yet like lettuce, you can pluck up to 30% of the plant leaves. Again, new leaves will grow back and you can extend the time your crops are in your system. If you transplant, you can cut the time to harvest down to around 6-weeks. One good thing with kale when grown indoors is that many pests don’t target it. Aphids being the primary culprit, yet they can suffer from powdery mildew.

The main varieties are Curly kale (common type sold in grocery stores), Lacinato kale (sweeter and have longer leaves), and Red Russian Kale.  This variety is the sweetest you can grow and has a reddish appearance.


Being another cool weather crop, this is perfect to grow along with lettuce and kale. Any temperature over 75 degrees fahrenheit will see the plant suffer. It can be grown from seeds and many hydroponic growers will place their seeds in the refrigerator for up to three weeks before planting. This creates a plant that is hardier and thus a healthier plant. They do like around 12 hours of light daily, however, because they are cool weather plants, T5 fluorescent lamps may be the better option for lighting.

When it is almost time to harvest, you can lower the temperatures because this has the effect of making the crop sweeter. However, because of this, growth will slow. It is advisable to go for quality over quantity to prevent a bitter tasting leaf.

Most systems are suitable for spinach, but just remember to plant them a few weeks apart so you can have continual harvests. A raft system can be perfect for these as it can be for lettuce and kale as well.


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Growing cucumber in hydroponics can be so rewarding. These vegetables love the conditions they are given. Warmth, nutrients and lots of moisture are perfect. Growers are amazed at the yields because they quickly become one of the highest yielding vegetables you can grow.

The ideal temperatures for optimal growth are just outside the ranges that the above leafy greens like. Saying this, they can grow in a range from 60 to 82 degrees fahrenheit. This makes them ideal for growing alongside the next two crops in the list.

Cucumber likes a pH of 5.8 with an EC between 1.8 and 2. Growers can find seeds expensive for a good hybrid strain, yet when you see what fruits one seed can bear once it is growing, this cost per seed is more than justified.

The hardest thing with cucumber growth is they are vining plants and will need trellises. This makes them more suited to flood and drain or other bucket type systems, where there is plenty of growing medium to help support. This being said, coco coir is one of the better mediums to use as long as the plants are supported well.

Be on the lookout for pests like mites, thrips, whiteflies, and aphids. These insects love to take advantage of cucumber crops.

Nutritious Tomatoes


When growers move on to tomatoes, it shows they understand their system and wish to go on to the next level. Having a continual supply of fresh tomatoes is what hydroponics is all about.  

These are a warm weather plant and like the temperatures like cucumbers. They do however prefer an EC level that begins at 2 and goes up to 5, so any system will need to be separated to allow tomatoes to grow on their own, or at least with other plants that like this level.

The ideal pH is between 5.5 and 6.5 and the temperature is between 58 and 79 degrees fahrenheit. The upper end of the range more preferable.

They can be planted from seeds, yet cuttings or seedlings are advisable because it takes too long to grow fruiting plants from seeds. There are many varying types, yet the vining varieties are popular because they are easier to control and harvest from.

Tomatoes as if cucumbers require trellises so they can grow upward, and they will deliver a steady stream of fresh fruits you can part harvest.

Tomatoes can suffer from various pests and diseases like spider mites, aphids, mosaic virus and much more. One other thing that can occur depending on tomato variety is they can be prone to splits. This is when the inside of the tomato grows faster than the skin. This often happens when they take up too much water in a short time.


Although most root vegetables are not ideal for growing hydroponically, radish are different. These are a cool weather crop so they can accompany the first few plants in the list. They also mature rapidly, and just happen to be one of the easiest plants to grow.

The pH is bets around 6 to 7, and the temperatures between 50 and 65 degrees fahrenheit. If you are growing a longer radish variety, these can withstand a bit more heat than the short bulb kinds. EC levels should fall between 1.6 and 2.2.

Lighting requirements are minimal, and at least 6-hours are needed. Optimal levels are between 8 and 10 hours of light.

Seedlings are not recommended, and they are better grown from seeds. From germination to harvest can be as little as three or four weeks. Add to this, if you stagger your planting, you can harvest all the way through the year. This cool-weather vegetable grows excellent in hydroponic systems where the temperature hovers between 72-76 degrees Fahrenheit.

The most common problems with radish is they can easily bolt if they are not kept mist, and if they are too wet, they can suffer from root rot.


Nearly every kind of bean can be grown in a hydroponic garden. There are hundreds you can choose from yet the most common are runners, string, pole beans and bush beans. These are easy maintenance and very productive for the effort which goes into growing them. Some types do take more effort because they are climbing/ vining plants so they will need support trellises.

When growing from seed, they are speedy germinators and can take less than two weeks. You may even see some varieties start in as little as seven days.

When growing and you can see they have two true leaves, then they are the right size to go into your garden. Depending on your system type, although ebb and flow being the better option, however, a drip system is also ideal. Plants should be planted around 4-inches apart when they are the bush variety. Pole beans should be spaced a little wider apart at around 6-inches.

One good thing with beans is they self-pollinate. Growing medium should be loose so hydroton pebbles or a mix of perlite and vermiculite are good options and have several advantages. With a neutral pH, perlite won’t affect your levels and expanded clay pebbles offer enough moisture and oxygen to the roots.

Twelve or thirteen hours of light is enough, and the daily temperatures should be between 70 and 80 degrees fahrenheit. If a temperature falls below 60, or rises above 60, then there will be a knock-on effect to the plants pod growth.

Beans don’t need many nutrients and when spacing them apart when planting, you can have a continual harvest. This can come in as little as 50 days for each plant.


Peppers are a great addition as they can be grown in any season. Not just this, but yields growers can experience are much larger than if they are grown by conventional means. This means fruits are larger and a better quality as the plants are delivered what they need to allow them to grow to their genetic potential.

Ebb and flow systems are best suited to this kind of vegetable, although they can be comfortable being grown in others which have a good base of growing media for support. These plants can grow quite large, so they need additional spacing of between 7 to 9 inches between plants. This can limit a pot to two plants only.

Lighting needs to be around six to eight inches above the plants and will need adjusting as they mature. If the bulbs are closer than this, it can cause scorching, and if further away, it can affect the yield or potential growth.

Lighting needs to be up to 12 hours per day, and no less than 10. Additionally, they will need sufficient amounts of nighttime hours as well. Daily temperatures need to be between 73 and 80 degrees fahrenheit, so they are perfect companions to be with cucumbers and tomatoes.

Extra attention is required during their growth where stem buds need pruning as the plants are about 8-inches in height. This helps the plant devote its energies into larger fruits than lots of smaller ones.

The pH levels need to be between 5.5 and 7, and the EC should fall in the range of 3 to 3.5.


Celery can be one of the harder vegetables to grow in a hydroponic environment, but it doesn’t mean it’s impossible. Celery seeds take up to two weeks to germinate, which is pretty long compared to other vegetables. A quicker alternative is to use the stalk of celery you purchased from the store.

If you take the stalk and cut 2 inches from the bottom, then place the base in a plate of room temperature water, it will actually start to grow after only a week. Celery needs a lot of water, so the proper system to choose would be a deep water system. Along with germinating seeds, harvesting celery can take up to 4 months total after the seeds are planted.

Celery likes a pH level of 6.5, and the EC level of the nutrients should be 1.8 to 2.4. This can be an accompanying plant in a grow room which is geared up for lettuce and cool weather crops. The daylight temperatures should be between 58 and 80 degrees fahrenheit. Lighting isn’t extreme and they only need around 6 hours per day.

It can take a long time to maturity and harvest, and they can test a grower who will need patience, however, growing this crop can be one of the most rewarding considering how expensive it can be from the supermarket.

Benefits of Hydroponics to Grow Vegetables

Using hydroponics to grow vegetables can be highly beneficial, especially in regions where conditions are not suitable, or those times of the year when nothing will grow. Many of the crops above can be grown around the year, or you can grow these while planting any of the many others, which aren’t on the list in a different growing season.

There are countless benefits no matter what you choose to grow, and here are a few you will see:

Larger Yields

Hydroponics can’t make vegetables grow larger than their genetics lets them, however, they can grow to their full potential and in a much smaller space than they can in soil. Being able to control the nutrients and pH levels in the water also ensures only optimal growth for the vegetables leaving little room for failure.

All Year Round Crops

As we just saw, because the gardener is in total control, they can use artificial lighting and warner indoor growing conditions to grow through the year. Crops that are out of season become expensive when they are shipped in, but having them a few steps away from your kitchen makes all the difference.

Less Space

Hydroponic systems can be built almost anywhere. They can be indoors away from any natural light, or they can be in outdoor areas undercover, or in a greenhouse in the garden. However, with a much smaller space, they can churn out many more crop harvests which is possible than if the garden was in soil.


When a hydroponic garden is up and running, they can easily produce more than enough food for a large family.

While some crops are not suited, there can be little need to purchase some vegetables ever again. Many growers begin by just growing for consumption, yet as they go along they find they expand and need to begin getting rid of vegetables because they are producing too many.

Family and friends will be thankful of tasty fresh vegetables, yet there are the shrewd growers who turn their gardens into small home enterprises.

The vegetables above are just the tip of what is possible with hydroponics. The choice of what you grow is up to you, but just the ones above mean you can have a wide variety of choice. Start with these and as soon as you gain more knowledge, or you find you have that extra little space, you can expand and tackle herbs, strawberries or anything else you find is hard to come by where you live.

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How Big of a Reservoir Do Hydroponics Need?

When any grower begins looking at building a hydroponic system, one of the main components will be the reservoir. Because the entire process revolves around water, this will need a home that is worthy of the life giving essence that the water provides.

The question arises for many growers because they may be trying to figure out what will fit where in their designated growing area. “How big of a reservoir do hydroponics need?” There is a general rule for this, which we will see, yet there is much more to determining the size of a nutrient reservoir than just having one of a specific size.

Carry on reading for all you need to know about hydroponics tanks and how you can be sure you have one that will meet all the needs of your system.

Do You Need Hydroponic Reservoirs?

Reservoirs are a fundamental component of any system. If it weren’t for these, there would be no place to put the water and nutrient solution. There are a few aspects to go through rather than just thinking a reservoir of a certain size is good for a given number of plants.

One of the first to know is that the size can change depending on the type of system you are looking to run. However, no matter what system you are using, the consensus is that the bigger the reservoir, the better it is for your system.

The reasons for this are a larger tank can help with pH swings, nutrient solution fluctuations and the depletion of oxygen. As soon as any of these factors are affected, then there is a knock on effect with the rest of the system and the plants.

You can add to this how the environment plays a role in the operation of a reservoir. Plants will change their uptake of water and nutrients depending on the environment, and if the humidity is lower than the ideal 60 and 80 percent, and is lower than forty to fifty percent humidity will cause plants to take up much more water to compensate.

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If it were just a basic calculation to determine the reservoir size, this would be easy. As a rule, there should be the following:

  • Small plants: 1/2 gallon of water per plant
  • Medium sized plants: 1 – 1/12 gallons of water per plant
  • Large plants: 2 1/2 gallons of water as a bare minimum

Although these are the recommendations, many seasoned growers will double these volumes without a second thought just to be sure.

How Do Systems Use Reservoirs?

Here is a quick look at the different systems and how a reservoir fits in with their design.

  • DWC (Deep Water Culture): Plants are suspended over the top of the reservoir. The solution will be highly oxygenated as no water pump is used.
  • Ebb and Flow: The reservoir sits under the flood table. Using a timer, this is flooded periodically. Once the timer cuts off, then the solution drains back to the reservoir.
  • Drip Systems: Reservoirs sit lower than the plants. A pump will feed solution through small tubes where it drains through the growing media and makes its way back to the reservoir using gravity.
  • NFT (Nutrient Film Technique): A thin stream of water is continually pumped into the highest point of troughs or channels. Plants are suspended over this so their roots can hang into the solution. Gravity is the usual means of returning the solution back into the reservoir.
  • Wick Systems: A thick rope will sit in a reservoir and feed up to the growing medium in a container sitting on the top. Plants will be fed by this wicking action, which delivers nutrients upward.

The Roles of Hydroponic Reservoirs

Here are the areas where reservoirs help to keep systems running at their best. As we have just seen, each system can use their own reservoir in a different way. However, all the following will be common, regardless of the system, the plant type or the location.

These few areas are what makes your system tick and stay healthy.

Nutrient Preparation

Your reservoir is the ideal place where to mix your nutrients. Some growers may mix in a separate container and then add to the reservoir, yet this makes little sense to add more work into the equation.

In an ideal world, you should have a spare reservoir, and this is where you will be mixing your next batch while one is in use.

Water Oxygenation

Without oxygen, plants die and will die quick. Depending on the system type, these solutions need lots of oxygenation through the use of an air pump. This then has tubes running into the mixture, and air stones or air diffusers convert this into tiny bubbles, which the water absorbs.

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While some of the systems use the water cascading back into the reservoir, this doesn’t deliver as much oxygen as a good air pump.

Concentration of Nutrients

As water is taken up by your plants or water levels drop by environmental factors. This means the concentrations of the nutrients increases. This will be very different from when you first mixed the batch, and will make it harder for plants to absorb what they need in the right amounts.

Your solution will need continual testing and adjustment as is required. Yet, the larger your reservoir, the rate at which the solution changes concentration is somewhat diminished. This can help reduce the amount of testing, and space out the intervals for replacing solution.

A good EC (Electrical Conductivity) meter can take a quick reading and let you know the levels of nutrient concentration. There is no way at present to determine what levels of each nutrient there is in the solution.

Ease of monitoring and adjusting solution pH levels

Just like EC levels, the pH of your solution will fluctuate. This can be from a change in concentration or there is a change in the temperature. Holding a pH in the desired ranges is vital for the health of the plants.

When you have a change in pH, this can lead to nutrient lockout or nutrient toxicity if it swings the other way. The larger the reservoir, the slower the rate of change of your pH. This makes testing more straightforward and not required as often. You can find adjusting pH is easier when there is a larger amount of liquid.

Solution Temperatures

A small reservoir can heat up much faster than a larger volume of water. Plants like temperatures between 68 and 75 degrees fahrenheit for their solution. It doesn’t matter if you live in colder areas or warmer, this larger volume of water is easier to control once you heat or cool it.

One sure way to help with maintaining solution temperatures is to use insulated reservoirs. These will help even more in keeping the temperatures stable without the use of a hydroponic water chiller or heater.

Reservoir Considerations When Choosing

Before purchasing any reservoir, there are some things to consider aside from the above. While all tanks may appear appropriate, this isn’t the case.

In this section, we will look at all the factors, which can determine your final choice of reservoir for your hydroponic system.

Reservoir Construction

Many gardeners construct their own systems. This leaves the choice of materials for their reservoir very different from if they were purchasing one. While it leads for lots of creativity, this is often done more for cost saving.

Large plastic totes can hold massive amounts of water, and thus can be a viable solution. However, once these are filled, it can lead to issues, which are not noticeable in the beginning.

Once these containers get warm over time, they begin to deform and bulge outward. There are many reservoirs, which are made from durable and sturdy materials that are a better choice. Barrels or large picnic coolers can be great options, and in most cases, they will be made from food grade materials such as polyethylene.

Reservoirs Need Lids

Depending if you construct your own reservoir, or purchase one specifically will determine if it comes with a lid. While these don’t appear to be too important, they are in fact crucial for a couple of reasons.

A lid on your tank can reduce the evaporation of your solution, this helps maintain the EC and pH levels to what they should be.

Reservoir Color

Aside from a lid preventing evaporation, there is the fact that as light begins hitting your solution, there will be algae growth. Algae can deliver a whole host of issues like depleted nutrients and oxygen from the water.

The time between cleaning this growth from your tank can also reduce. While dark colors are a recommendation to prevent light seepage, these can absorb heat from grow lights. Covering tanks in silver foil or insulation can help keep light out and keep your solution cool. It is worth noting that warmer solutions can’t hold dissolved oxygen as well as colder solutions

Tank Location

This can depend on the kind of system you are running, but not only that, once they are full of water, there is no way you can relocate them.

Your reservoir will need to be out of any direct sunlight and it should ideally be close to a water source and a drain. This can make topping off and cleaning that much easier. One other thing that may have a bearing on this is the system type.

Many tanks sit under the bed of the system. Accessing the tank while the garden is in use can be very difficult. There will be hoses, pumps and pipes all over the place, which can be hard to dismantle to gain access. There is also then the consideration of how close the tank is to the grow lights. Hence the dark color and the silver insulation.

Care and Cleaning of Nutrients and Reservoirs

A reservoir and the solution it contains will only be as good as the care and attention it receives. It isn’t possible to fill one and then expect everything to be fine until it is almost empty. Here are some things to know about the care and attention for both elements.


There are many methods of testing solutions to be sure the levels are correct. While you can use manual means of doing so, these are not as effective as meters, which can make these readings in a much shorter time.

There are expensive automated means of doing the same thing, yet meters are not worth anything if they are not used. It is possible to purchase multi-purpose meters that are capable of taking readings of different elements like pH, EC and the PPM/TDS.

Many gardeners now use this kind because of the timesavings when testing. Not only this, but they are more accurate that manual testing means. One thing to be sure of is that any device you purchase can have manual calibration. This can prolong their accuracy and their life while reducing errors.


We have seen how vital dissolved oxygen is for plant health. The best ways to do this are through air pumps and air stones. The benefits are still being seen, so it is better to have more oxygen in your water than too little.

The other plus side of this is it prevents water stagnation and keeps nutrients being continually mixed and stimulated. This aeration can actually help with the nutrient uptake by your plants, and thus helping promote plant growth.

One area, which may not be seen by new growers, is that this aeration can help prevent any development of pathogens. Rather than any anaerobic bacteria forming, there is the growth of many other organisms that are beneficial.

Topping off Tips

Every grower has to top off his or her tank at some stage. Up until this stage, there will be lots of testing and waiting. However, levels will begin to drop the longer the system is running. We saw that nutrients strength increases because water take up is higher than nutrients.

This means that water needs adding to make sure plants have enough, and to dilute the nutrients before they become toxic. However, there is only so many times you can top off a hydroponic reservoir before the nutrient solution becomes too weak, and you are in need of mixing a new batch.

When first filling, you need to mark the high water level on the inside of your reservoir. This will need checking daily, and you can top off up to that level as required. This happens every few days rather than daily.

While doing this you will need to keep a check of how many gallons, you add. A good rule to follow is that once you have replaced 50% of the original volume, then this is time to consider flushing the system.

Reservoir Flushing

It doesn’t matter how large and how good this larger volume of solution is at buffering changes in the nutrient levels or the pH. There comes a time when you top off the the extent that the solution is weak, there is debris in it, or you are having issues with nutrient deficiencies you just can’t work out.

Having a clean tank is the ideal way to solve most problems, and it is the only time you know what your levels are. There are long conversations and debated when the best time for system flushing is, yet you can find that even if there is no real right time, there is definitely no wrong time.

It can be as little as a few days before your levels start changing from the ones you set, so it is easy to see why this system flushing occurs on a regular basis. Some gardeners may flush weekly, while others recommend bi-weekly. This is true for vegetables, which can take on a bitter taste through too much nutrient absorption.

Hobby gardeners can follow this and flush more often than not. This can resolve issues from beginning without affecting their plants.


As we can see, there is no real upper limit on size of hydroponic reservoir, yet being realistic does come into it. The main thing to consider is that you don’t choose one, which is just the right size or smaller. This can leave with continual issues you need to deal with, and you have no way to turn to offer a solution.

You can see why gardeners come up with the recommended size by the number of plants and the volume of water for each plant before doubling it. These buffers can make all the difference between healthy crops and a failed crop.

With the reservoir, that is the ideal size, and if possible, a second where to mix and use as the other is out of commission can lead to less downtime and a healthy yield from your garden. For the gardeners who can’t afford or fit in a second tank. All the above information should be enough to make sure their primary tank is large enough and cared for to give a healthy system.

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How Often Should You Fertilize Hydroponics?

One of the main questions which catches new growers out, is that of how often they fertilize their hydroponic system. Once their systems are up and running, this frequency can be a lot less than many growers think.

As a general guide, if you are remixing your nutrients between 7 and 10 days, then just topping off your reservoir with plain water will be sufficient. However, you will need to check daily because the strength of your nutrient will change as plants take up water.

The nutrient levels should sit in a range of between 800 to 1500 ppm (parts per million), this can vary depending on the kind of plants being grown.

Here we will look more in depth at how you need to set your reservoir and maintain the right levels of fertilizer and nutrients. We will also look at two ways growers determine the right times to add more fertilizer to their system.

Selection and Preparation of Nutrient Solutions

When it comes to hydroponic nutrients, you can go about this a few different ways. You can purchase ready-made solutions, you can buy nutrient solutions which come in two or three parts or you can make your own from scratch.

For growers with small gardens, it is advisable to go with the two- or three-part solution. This allows you to be flexible and tailor your nutrients to the type of plants you are growing, and the stage that they are at in their growth.

There are a few factors, which determine the proportion of nutrients you use in your system. This will be the same regardless of the way you get your nutrients from the above three methods.

  • Plant type and variety
  • Growth stage of plants
  • Plants parts you want to encourage growth and development
  • Intensity of light, weather, season and grow room temperatures
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If you decide to go with a ready-made solution, be sure it is made specifically for hydroponic systems. Fertilizers, which are developed for soil lack many of the micronutrients required as these, are already found in the earth.

How EC Levels Affect Hydroponic Nutrient Solutions

To determine the nutrient concentrations in your solution, you will measure the EC (Electrical Conductivity) – we’ve written a complete guide which you can find here. To do this, you will use a digital EC meter. Once you take a reading, this will be converted into the dissolved solids, or as we know them the PPM (Parts Per Million).

These EC meters can help when you are mixing your solution, and it is at the correct solution, and they can help monitor the concentration over time.

One thing to note is that EC levels will never weaken on their own, and will always become stronger as plants absorb water faster than they absorb nutrients.

These EC meters are vital and will help growers to prepare their solutions, monitor their concentrations, dilute these as necessary and know when it is nearly time to fertilize their system again.

EC Reading Problems

As helpful as EC meters are, they are not the solution to everything. While they are capable of giving you the PPM of your solution, they cannot differentiate between the various compounds of your nutrients. This can be a problem if you live in a hard water area, and a fair percentage of your PPM comes from unknown dissolved solids in your water.

Hydroponic Nutrient pH Levels

Once you have your initial mix, it will have a specific pH level. Depending on plant types, the optimal levels are around 5.5 to 6.3 in hydroponic systems. Each type of nutrient will be absorbed by your plants at varying rates, depending on the pH levels of your solution.

Solutions, which have a drop of under 5.5 of their pH, run the risk of having deficiencies in some nutrients while others are having a toxic effect as they are being absorbed too quickly.

If the pH rises too much, this can lead to speedier evaporation of micronutrients from the solution. This will lead to deficiencies in certain nutrients.

Checking pH levels is required almost daily, and sometimes, more than once per day. As plants continually absorb minerals and nutrients, pH levels will change, as will the overall EC / PPM of the solution.

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We’ve written complete guides to testing your pH levels, and showing how to balance your pH if it’s not quite right!

Topping Off and Adding Fertilizers

This is two parts of the same area in your system. With the above, we saw ways for a grower to understand what is happening with their nutrient levels inside their tanks.

It is from here that you can find when to add, or how often you should fertilize your hydroponic plants.

Once you run your system, test your levels and once everything stabilizes, you will see that your water levels drop as your plants absorb fluids and nutrients. Aside from this, there will be a loss of water through evaporation.

When you first fill your tank, you should mark the high water level. You should check water levels daily and only top up to this mark. Depending on the type of system you have, you will top off every few days. It is here that plant type and temperatures come into play.

As you add water to your tank, you should record how much you add, it is this that can help you determine when you need to flush your system.

As you progress with your system, you will come to find that no nutrient mix is perfect, and there will be problems along the way. For this reason, flushing a system is vital to have a fresh start and correct any imbalance in your system. pH swings or EC levels that are totally out of balance being the main things.

This flushing of systems comes under much debate and discussion. You will also find that this determines how often you fertilize your hydroponic system.

Adding Fertilizer after Flushing Systems

There are two ways that growers look at when to flush their system and thus introduce a new set of fertilizer to their system. A general rule, which is often used, is that reservoirs will be emptied and re-filled no longer, than ten days into any growing phase.

This will be the extreme case because it will be determined by EC levels. On average, the time to change would be between 5 and 7 days. However, these EC readings can cause the issues. Because they give an overall picture, it is hard to know which nutrients are at what levels.

Growers who follow these methods will do so because it is the only sure way of knowing what levels of each nutrient they have in their system.

The second method of adding fertilizer to your system goes a little further than the above. If you are rigid with a ten-day flush, then you can waste precious nutes.

The second way uses the 50% method. This looks very similar to the above yet it doesn’t have a set time associated with system flushing.

The way this works is to measure your reservoir when you first fill it, and record the number of gallons. Check your levels every couple of days and top up with plain water. You proceed in this manner until you have replaced 50% of your starting number of gallons.

Once you have replaced half the liquid, you then cease topping off your tank and let the solution levels run down until they reach the top of your water pump.

At this stage, you can clean and drain your tank, and then add a new batch of nutrients or fertilizer.

One tip when using this method is for flood and drain systems. Because there can be salt buildup, it is advisable to flush your growing pots, growing medium and also your plants to rid them of accumulated salts.


As you can see from the information above, you will in act fact only fertilize your system once at each stage of growth. This, of course, will vary depending how long it takes your plants to grow from seedlings until harvest.

Both of the methods above may be suitable for many growers, however, the 50% method will cut down on waste. However, as the nutrient solution will be weakened by half, you may begin to see slow-growing plants showing signs of nutrient deficiencies toward the time you are almost ready to flush your system, and add a new batch.

Finding the method, which is best for your garden, is straightforward, and monitoring pH and EC levels can be the easiest ways to make sure you have this control. One final note is that you are better to add less rather than more when it comes to hydroponic nutrients.

Related Questions

Why should I not add more nutrients when I top my system up with water? The reason for not adding more nutrients when you top up with water is that the concentration becomes stronger. When this happens, certain compounds become toxic to plants.

How does weather affect nutrient requirements? Plants will have higher nutrient requirements in the colder times of the year; they will also have a lower requirement in the hotter months when they need to take up more water. However, if your grow room is always the same temperature, or never falls below a set temperature, then this scenario should never occur.

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How to Keep Water Cool in Hydroponics: 8 Easy Ways

One thing growers should never overlook in their hydroponic system is the temperature of their nutrient mixture. As soon as the temperature reaches over a certain point, the solution can’t hold the dissolved oxygen as long.

Add to this, when there are unhealthy root masses mixed with these temperatures, it creates the perfect place for pathogens like root rot to take a foothold. To combat these problems, you need to make sure your nutrient solution remains between 65 and 75 degrees.

Here we will look at ways to cool your hydroponic reservoir and solution. While these can make the difference, some of these methods come with their own downsides when in use.

In summary, according to other sites such as NoSoilSolutions and Epic Gardening, here are the main eight ways to cool a nutrient reservoir.

  1. Keeping your reservoir in the shade
  2. Paint your reservoir to reflect light
  3. Increasing the size of your reservoir
  4. Top off your nutrient solution
  5. Bury your reservoir in the ground
  6. Making a swamp cooler
  7. Making your own cooling coil
  8. Purchase a water chiller

How Can I Cool My Hydroponic Reservoir?

Here we will take an in-depth look at the above methods. The first couple of entries in the list should ideally be done as a matter of course. Aside from controlling temperatures, they help prevent light entering and the growth of algae.

1# Keep Your Reservoir in the Shade

Any grower should be doing this one thing by default. Being able to minimize the amount of light which falls on your reservoir will help prevent it from warming up in the first place. Aside from this, you also need to be sure no light is entering your reservoir, this will warm it quicker, and it does allow algae to form along the water line.

2# Paint or Insulate Your Reservoir

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There are two things you can try in this solution. The problem doesn’t just come from tanks, which are in a warm environment. Nutrient tanks can catch the heat from grow lights. As soon as this starts to hit the dark colors of your tanks, then the solution inside begins to warm up.

Solutions for this are to either paint your reservoir a light color as a way of reflecting the light and the heat, or you can cover your tank in a reflective insulation material. Even regular insulation can be enough to help maintain cooler temperatures in your tank, yet reflective insulation comes with an added benefit.

Once your grow lights hit the top of your tank, this reflective material bounces light back, which can reach the undersides of your plants.

In summary, here are things to know about painting or insulating your tank:

  • Don’t choose a light plastic to save on painting, this can lead to algae growth when light passes through
  • Dark plastics absorb more heat while light colors reflect
  • Reflective insulation helps cool, and throws light back onto your plants

3# Increase Your Reservoir Size

Depending where hydroponic gardens are located, this often dictates the size of reservoir in use. For small gardens, growers tend to go for a smaller tank to match, however, these warm up quicker than larger reservoirs.

If you add a larger reservoir, your nutrient mix becomes more stable. This doesn’t just mean you can keep lower temperatures, but also it helps balance pH levels, PPM and other concentrations in your mixture.

  • Small reservoirs fluctuate easier
  • Large reservoirs add stability for controlling temperature and other factors
  • PPM, EC and pH are easier to control in larger tanks

4# Top Off Your Solution

If you need a quick fix, then this can suffice to drop your temperatures down a few degrees on hot days. This method shouldn’t be used too often because either you will be diluting your nutrient mix, or you will be using more nutrients than you need to.

It is better to use this method in case of emergencies because if you have temperature fluctuations, they will always be there, and this method doesn’t do much to eliminate them.

  • Not to be used all the time
  • Add cooler solution slowly so not to shock plants

5# Bury Your Reservoir

This method only works if you have an outside hydroponic garden. You can prevent several problems with your nutrient tank by burying it. This helps to maintain cooler temperatures but using the natural coolness of the earth, and it is sure to stop any light from entering your tank.

The main things to remember with this method are you may struggle when you come to flush your tank between growing. If it is already under ground level, you may not have a suitable drain point.

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6# Make Your Own Swamp Coolers

Swamp coolers are effective, and very simple to make. All it requires is to take a suitable fan and blow this across the top of your nutrient solution. As a result, you may see temperature drops of around 5 to 10F.

The downside to this is you can be topping off your reservoir more often to compensate for evaporation. Second to this, your EC and PPM levels will rise that will require continual adjustment. You may also find using this method, you are allowing light into your tank.

7# Make a Cooling Coil

While these can be effective, they do take more work and they have the downside of wasting water. To make one of these, you can take copper or stainless steel tubing and form it into around 20 coils. This will then sit inside your reservoir with a hose connected to both ends.

One fits on the faucet while the second drains. In operation, the water trickles through the tubing and will pull heat from your reservoir into the liquid inside.

  • Wastes water
  • Can offer unlimited cooling at a cost
  • Doesn’t need any power

8# Buy a Water Chiller

One of the most efficient ways to cool your reservoir is to purchase a water chiller. These deliver a hands free approach and give you lots of control. These do become more cost-effective if you have more than a couple of tanks where you need to control the temperatures.

These water chillers can be a hefty investment, and they do consume electricity for their operation. There are varying sizes so scaling up to any sized garden can be straightforward.

  • Most expensive option
  • Still requires water pumps
  • Can be a set it and forget it solution
  • Ideal for larger gardens

Ideal Hydroponics Temperature 

Plants thrive better when they are in a constant environment. While nutrient temperature can fluctuate, the main problem can stem from the grow room itself.

For ideal temperatures for good plant growth, the surrounding environment should be around 70 to 80F. For optimum root growth, the ideal temperatures of the root zone should be around 66F. 

Once the temperatures are above these, then stress starts to show in your plants. Heat stress can cause plants that are spindly in the early stages of growth, and mature plants can fail to fruit or flower correctly.

Most of the above methods focus on cooling a nutrient mix which is already warm. However, to have the perfect grow room will mean that your tanks temperature doesn’t climb in the first place.

Here are some of the best ways you can help maintain your grow room environment.

Air conditioners: This works as well as a water chiller, but for the surrounding environment. The environment will warm because of grow lights, or any natural light, which spills in through windows. You can purchase window type air conditioners that are ideal to cool your grow room enough without breaking the bank.

Relocate or Insulate Grow Rooms: The biggest culprit for tanks heating up will be your grow lights. If your grow room faces the south, or your grow room is under a hot roof, you may be fighting a losing battle with your tank temperatures.

Insulating your grow room can prevent hot weather having an impact. Additionally, if you can move a grow room into the basement, you will find it is naturally cooler than above ground level.

Increase Humidity: If your grow room suffers from low humidity, then your plants will take up more water to keep cool. This is where your tank levels drop faster and thus warm up quicker. Misting your grow room can keep plants and the surrounding areas cool, and as a result, your nutrient mix will remain stable.

Improve the Air Flow: Plants require good air circulation for healthy growth. This will also help prevent your nutrient mix from warming in the first place. Plants will benefit with circulating air, and it stops pockets or warm zones from forming around the grow room.

Run Lights at Night: One-Way of cooling a grow room which many growers often overlook is using their grow lights at night rather than in the day. Using supplemental lighting at night not only offers cheaper electric in some cases, but a grow room will be cooler at this time. The overall temperature of the room may not reach a level that will push your reservoir up to the higher limits to cause problems.

However, doing this will mean you need alternative counter measures in the day to cool your grow room. This will depend on the location as to the extent you need to go. If your grow room has access to natural light, it can be just a matter of extra shading, additional misting and fog to keep lower temperatures.

Calculating the Size of Water Chiller

One of the most crucial factors when choosing a water chiller is how well it will perform on your system. It isn’t just a matter of choosing one and expecting it to cool sufficiently. When it comes to the sizing of your water chiller, the following method allows you to determine the size of chiller unit that is sufficient for your garden system.

  1. Calculate your system volume – this includes all buckets and tanks
  2. Run your system with everything turned on – all grow lights, fans, etc.
  3. When your grow room has reached its max temp, take a reading before cooling your system using ice packs or frozen plastic bottles of ice.
  4. When your system mix cools, remove the ice and run for another hour.
  5. After this time, take the water temperature
  6. Subtract your ending temp from the starting temp
  7. Use the formula to find the minimum BTU required.
  • System volume: 80 gallons
  • Desired Temp: 65F
  • Running Temp: 76F

Formula: 80 x 8.34 x 11 = 7,339 BTU (gallons x weight of water x temporary difference).

A water chiller should run around 20% above your BTU requirement minimum to counteract performance loss.

Pros and Cons of Using a Water Chiller in Your Garden

Like many things for your hydroponics system, there are pros and cons of using a water chiller.

Pros of Hydroponic Water Chillers 

  • Cooler temperatures enable your solution to hold a higher degree of dissolved oxygen. This is the key basis of increased nutrient uptake and explosive root growth.
  • Highly oxygenated environments, which come with cooler temperatures, can help deter pathogens from taking hold.
  • A cooler reservoir will act as a heat sink in your grow room. This can draw ambient heat and help to cool the whole room

Cons of Water Chillers in Hydroponic Gardens

  • Expense is one of the largest primary cons for a water chiller. Although you can find affordable models, it can still be a cost that many growers can’t justify.
  • Noise – in operation, these will sit outside of a reservoir like air pumps. They will make the same sort of noises as air conditioning units.
  • Heat: Water chillers do generate heat when they cool water. Either they require ducting to transfer this heat out of the grow room, or they have to sit outside the grow room to not introduce more heat.

Why Do Roots Need Cool Temperatures?

Root zone temperatures affect overall shoot growth. Not only this, the impact from the root zone temperature will have more of a bearing on development and overall growth than the ambient air temperatures.

This occurs because the tissues of the roots send messages to the shoots. This will have an effect of how the shoot reacts to the environment. Growers see that there are many functions that occur for the plant in the roots, and thus, the root zone temperature becomes crucial.

Such is the effect of this, even thirty minutes of heat buildup in your nutrient mixture and in the root zone is enough to have a negative effect on your plants. One thing to note is that a daily cool average isn’t sufficient to counteract this.

As soon as your temperatures rise above 86F, then crops, which are sensitive to heat, will quickly falter such as lettuce or parsley.

When you look at something such as lettuce, the cooling of your nutrient reservoir does allow these crops to face higher than usual/ optimal temperatures above the surface.

While there are many biological happenings because of cooling roots lower than the ambient air temperatures, it is easier to know it reduces heat stress in the leaves of plants.

Root Zones and Different Hydroponic Systems

Cooling your nutrient solution to the optimal temperature isn’t all the equation. The remainder comes from the types of system you are running.

The root zone temperature needs to remain the same all the time. The cool mixture has a big influence on this, yet the system type and how it is built can affect this dramatically. A good example being the only system, which will have the same temperature root zone as the nutrients, will be a DWC system.

The roots are in constant contact with the solution. In all the other types of system, there is a degree of separation between the root zone and the reservoir.

A good example of how this can affect plants is in an ebb and flow (flood and drain) system. As your cool solution rises in the flood tables, the plants gain the advantages of oxygenated water and the roots are comfortable because of the lower temperatures.

However, things change as the cycle stops and the solution begins to drain back into the tank. Warm air from the grow room can be pulled through the growing medium as the solution drops. If the environment is warm, it can heat up your root zone considerably until the next flood cycle.

Unless you have a good means of cooling your solution, this will transfer heat back into your tank and thus warming it with each fill and drain cycle. Depending on your cooling solution, you may find that this is insufficient and as much as you are trying to cool your water, it increases in temperature regardless.

Not only will your water increase in temperature but also the root zone can be at a damaging temperature between your flood cycles.

Size of Your Hydroponics Reservoirs

One of the first things to be sure of is that you have a large enough reservoir. Rather than just being large enough for the size of system, you have, you are better to have a much larger one than you require.

Hydrotek, who are one of the largest names in hydroponic equipment recommend the following for reservoir sizes:

  • Small plants – ½ gallon for each plant
  • Medium plants – 1 ½ gallons for each plant
  • Large plants – 2 ½ gallons for each plant

Hydrotek recommends you choose a reservoir that is at least double the size.

You also need to consider how thirsty your plants will be. This can use your water and nutrients faster, such as is the like of tomatoes in comparison to lettuce.

This will use your mix faster and thus cause a warm solution once the level starts to drop.

Using all the above information can help to maintain cooler temperatures for your nutrient solution. However, if you find your grow room comfortable for yourself as you are working in that environment, then you are halfway to knowing how it feels for your crops.

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9 Flowers to Grow in Hydroponics (with pictures)

Why Hydroponic Flowers?

Flower gardeners spend countless hours tilling and tending to the soil. This makes flower gardening appear hard work, and if it takes this much effort, then why would you consider growing plants in a hydroponic system?

There are in fact several benefits and advantages flower gardening in hydroponics has over soil growing.

Results come much faster, you can tailor your nutrients to each plant species, and you have no weeds, insects and less disease to contend with. This delivers an up to a fifty percent faster growth in flowers, and yields are much greater than compared to soil growth.

With this in mind, you can now grow flowers all year round, and which can be expensive to purchase when out of season. You can also have as many cut flower displays around your home as you wish.

Before an in-depth look at each flower, here are nine of the best flowers you can grow in your hydroponic system.

  • Peace lilies
  • Hoya
  • Snapdragons
  • Dahlias
  • Rex begonias
  • Carnations
  • Orchids
  • Petunia
  • Zinnia

Top 9 Hydroponic Flowers

Peace Lilies

As an indoor plant, the Peace Lily can be one of the easiest to care for. You need the right growing conditions though. These tropical flowers are part of the Spathiphyllum family and are recognizable by their dark green leaves and white flowers.

While we can grow these in a hydroponic system, they don’t like to be over-watered. They can in fact be more tolerant to under watering than being around too much water. Peace Lilies, which grow in a hydroponic system, are often adapted versions where they send out small roots to absorb water. Here you can see Peace Lilies grown in small aquariums.

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Many growers often wait until leaves show signs of wilting before watering, this can prevent over watering. If they are over watered, it can lead to root rot, and the plant will suffocate.

Tips for Growing Peace Lilies Hydroponically:

  • Peace lilies like a temperature range of 68 F to 80 F. This will deliver optimal growth.
  • Clean leaves and you can reduce the risk of pests. The most common being aphids and mealybugs. 
  • Be sure to keep your lilies in warm draught free areas
  • The ideal pH range would be from 5.6 to 6.5.

Fun Facts about Peace Lilies

  • Despite the name, peace lilies aren’t related to true lilies.
  • NASA studied Peace Lilies because of their air-purifying abilities. They show them to be effective at removing formaldehyde, carbon monoxide and benzene from the air.
  • All parts of the Peace Lily plant can be poisonous as they contain calcium oxalate. If ingested in sufficient quantities, this can cause respiratory and stomach irritation. You should keep away children and pets from Peace Lilies.
  • Indoor varieties can grow up to around 16-inches while outdoor types can grow up to six feet in height.


Hoya plants are better known as the wax plant. These are a vine, shrub, and evergreen perennial creeper. When flowering, they adorn some gorgeous star-shaped flowers with leaves that can either be smooth or feel like soft felt. Hoyas are very low maintenance, which is one reason they are so popular for a houseplant.

Hoyas are another plant that doesn’t take to over-watering. Depending on the growing conditions, Hoyas can have flowers 1/4 inch in diameter up to 4” in diameter. There are many different Hoya’s choosing from, 200 species to be exact, and they all boast their own unique colors and shapes. So choosing the hoya, you desire is half the battle to growing and nurturing them.

Tips for Growing Hoya Hydroponically:

  • When pruning, avoid cutting the long tendrils, these are where flowers develop.
  • Hoyas require adequate drainage so they are not accidently over watered.
  • Likewise, this tropical plant can absorb moisture through the air, which is what makes it so low maintenance. Consider a system that uses humidity.
  • Hoyas prefer bright indirect light. What they don’t like are dark corners or direct sun. Hoyas can handle cooler weather from 50 degrees F up to warm temperatures of 77 F.
  • Maintain a pH range of 5.0-6.5

Fun Facts about Hoya

  • Even though there are over 200 different variations of hoya, you won’t find blue, purple, or violet colors represented.
  • Some species of Hoya have a Crassulacean Acid Metabolism
  • Each cluster of flowers on this plant can contain up to 40 individual flowers.


The botanical name for Snapdragons is Antirrhinum and means ‘like a snout.’ This plant is native around Europe and North America. They have become a popular favorite because of their vibrant hues, and their flowers that resemble a dragon-like mouth when pressed.

Mature Snapdragons can grow from 6 inches up to 48 inches depending on the variety, and the growing conditions. This means you may require some support for your plant, and the growing medium will need to hold them firm. Perlite is often the more common.

Even when grown in a soil-based medium, it’s common to grow flowers like snapdragons indoors before transferring them. This is because they are very sensitive to weather conditions. There are over 18 different snapdragons, and all these deliver bloom colors of pink, yellow, red, white, purple, peach, orange, and bi-colored.

Tips for Growing Snapdragons Hydroponically:

  • Snapdragons need adequate watering but not standing in moist conditions. Your growing medium will need to dry between cycles.
  • Snapdragons are perennials that require full sun with only occasional shade.
  • They prefer pH levels between 6.2 and 7.0.

Fun Facts about Snapdragons

  • Often called Dog’s Mouth, Lion’s mouth, Dragon flower and more depending where you are.
  • The leaves and flowers have some anti-inflammatory abilities.
  • We can apply them as poultices for ulcers or tumors
  • When snapdragons are mixed with tea, they can help detoxify the blood and increase urine production to clear the body from waste.


Dahlias are closely related to sunflowers, daisies, zinnia, and chrysanthemums. We know dahlias as octoploids, which means they have eight sets of homologous chromosomes.

If you grow these in your hydroponic system, you will need to be sure they have lots of space. As you are planting in a container, this does need to be at least 12 inches deep. Some varieties require deeper which can rule these out of your system. Dahlias grow half as wide as they do tall; so lateral space is important.

Dahlias like to have lots of light, and they are thirsty feeders. Your growing medium should dry out between watering schedules, and you will need to monitor your tank levels. Once planted, you will need to fertilize with a 10-10-10 NPK mix.

Tips for Growing Dahlias Hydroponically:

  • Dahlias need constant light to bloom and grow. It’s recommended that they receive a minimum of eight hours daily.
  • Dahlias are spring-planted flowers. This means they prefer warmer temperatures. Stick to a minimum of 60-degree temperatures and a maximum of 72 degrees.
  • If you prefer your dahlia’s being shorter and bushier, cut the center shoot above the third set of leaves to encourage shorter growth
  • Dahlias need a pH level range of 6.5-7.5.

Fun Facts about Dahlias

  • There are over 20,000 cultivars of Dahlia.
  • It’s the official flower of Seattle, WA although they are not native to the area.
  • Dahlias were known as a vegetable in the 18th century but later became more known as flowers.
  • They named them after 18th-century botanist, Anders Dhal.

Rex Begonias

Rex Begonias are unique in every sense. We do not know them for their flowers, rather their leaves and foliage. This is colorful and can be overlaid onto the thick fibrous leaves. It is possible to find a myriad of color options from maroon, lavender, gray, silver, pink and reds.

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Rex Begonias were first noted in 1856 when a shipment of orchids to England included the mysterious plant that no one could identify. This plant is tropical and native to South America, Africa, and Southeastern Asia. There are over 1,831 species of begonia, each with their own intricate and original leaf appearance.

Tips for Growing Rex Begonias Hydroponically:

  • Since Rex Begonias are tropical and subtropical plants, they are native to jungle types of environments. It is this, which makes them great as houseplants as they require little light and prefer shaded and cool areas.
  • These plants can grow from 12 inches to 24 inches in height. With leaves growing an average of 4-5 inches, it is also crucial to be wary of outward growing space requirements.
  • You can tell when the Rex begonia has received too much light, as the foliage will turn brown.
  • Stick to temperatures between 60 and 85 F.
  • Maintain a pH range of about 5.7 to 6.2 for optimal growth.
  • Rex Begonias like humid conditions; this may mean misting their leaves early in the day.

Fun Facts about Rex Begonias

  • You can propagate Begonias by using stem cuttings.
  • The Begonia stem is actually designed to store water so that during dry periods of the year, the Begonia remains hydrated.
  • Begonias only have a life span of about 2 to 3 years on average. They can live a few years longer if they live in an excellent and nurturing environment.
  • The juice of the begonia plant is thought to relieve headaches and as an eyewash for conjunctivitis.


Carnations are by far one of the most popular flowers to be grown in hydroponic systems. They are also one of the most commercially grown flowers because of the number of individuals who have them as indoor decorations.

Carnation petals have a fantastic aroma and make any room feel inviting when they have a presence. On top of this, the leaves can also be edible and are sweet to the taste. Growing from cuttings is often the preferred method. If propagating in soil, it can take between two and three weeks when from seeds. Hydroponics can speed up this process.

Tips for Growing Carnations Hydroponically:

  • Make sure carnations receive 5-8 hours of uninterrupted sunlight daily.
  • Carnations will thrive the best with a pH level of around 6.0.
  • Rockwool starter plugs are ideal for seedlings up to 4 to 5 inches in height, at this stage, we can transplant them.
  • Keep the temperature range of 65 to 75 F.
  • Ebb and Flow, Dutch bucket or DWC systems are best suited to Carnation growth. They will need support when they grow.

Fun Facts about Carnations

  • Carnations are believed to be native to the Mediterranean area. However, because of extensive cultivation over the last 2,000 years, no one knows for certain where their origins lie.
  • Annual carnations, border carnations, and perpetual flowering carnations are the most common types that are grown.
  • Greeks and Romans used carnations in garlands.
  • Carnations are a bisexual flower. This means they have both male and female reproductive structures that inhibit better growth and production.


For many people, Orchids are among the most beautiful flowers there are. Around the globe, they are a gardener’s favorite thanks to their woody-thick roots and colorful blooms. One thing many lovers of this plant are unaware of is, around the world, most of these are actually grown in hydroponics systems.

The reasons for this that where these Orchids grow in tropical climates, they latch themselves to tree bark or in between rocks. As the climate can be wet, it exposes them to sufficient watering from the rain. Once the rain stops, it exposes the roots to the air and can have plenty uptake of oxygen.

Add to this surrounding organic matter which rots, and they have a steady stream of nutrients. This is hydroponics in its purest form, and it is what makes growing Orchids in a proper system so easy and so rewarding.

Tips for Growing Orchids Hydroponically:

Fun Facts about Orchids

  • The flowers on orchids can survive for up to 6 months.
  • Out of the millions of seeds that orchids produce, less than a hand full will develop into a plant.
  • Orchid seeds do not contain endosperm, which is what they need to provide nutrients during germination. Because of this, they require symbiosis with fungi to achieve germination. Germination of orchids can sometimes take up to 15 years.
  • They use orchids in the perfume, spice, and medicine industries.


These popular South American flowers can withstand hot climates. They are widespread around many gardens in borders and in pots. There is an almost endless range of colors available, which is one reason they are gardeners favorites.

Most Petunias you see for sale are hybrids and are developed for specific purposes. As they grow, they can reach anywhere from six inches to four feet in height and have a spread of up to three feet. This means you will require support and lots of spacing to avoid overcrowding.

Tips for Growing Petunias Hydroponically:

  • Petunias need at least 5 to 6 hours of full light to thrive at their best.
  • When fertilizing Petunias like a balanced mix of 8-8-8, 10-10-10 or 12-12-12.
  • In germination, your Petunias will prefer warmer temperatures, however, once they have germinated, move them from this warm area so they can grow in cooler areas. They prefer cooler temperatures between 57 and 65 degrees Fahrenheit.
  • Petunias like pH levels of 6.0 to 7.0.

Fun Facts about Petunias

  • Petunias are an annual plant, so a full life cycle takes one year.
  • Common Petunias are edible and have a sweet and spicy flavor
  • There are four groups, which all Petunias fall into. Grandiflora, Multiflora, Milliflora and Hedgiflora.
  • Petunia comes from the word “Petun” which means tobacco in Brazil. These two plants are related and can be crossbred.


Zinnia are easy to grow and are a part of the daisy family. Being native to Southwestern United States and South America, they like to grow in full sun. At least six hours of full sun or bright light are recommended to get the best of these colorful plants.

Once they grow, they can range between 4 and 40 inches in height. This means you will require some support and a growing medium that can support their root system.

Their large range of bright colors and ability to withstand hotter climates makes them popular for planting in many a garden environment. Zinnias will reseed themselves each year. When selecting from the many varieties for your hydroponic garden, you will be better off selecting the more compact varieties.

Tips for Growing Zinnia Hydroponically:

  • Keep the temperature range between 74 and 84 degrees Fahrenheit. They can grow in temperatures as low as 60 degrees Fahrenheit.
  • Zinnias like moist environments yet they don’t like to be over-watered because they can fall foul of root rot. It can cope with dry spells better than standing in water
  • Once flowers show, they can benefit from 5-5-5 fertilizer for larger blooms.
  • Zinnias prefer pH ranges between 5.5 and 7.5.
  • Zinnias like a lot of light, but they can do just well in environments that receive less than 6 hours of light minimum.
  • If you want bushier plants, you can pinch the growth tip of the plants when young. This creates shorter side branching plants.

Fun Facts about Zinnia

  • Zinnia leaves have a sandpaper-like texture to them.
  • They named them after the German botanist Johann Gottfried Zinn.
  • They can have a single, semi-double or even double layers of petals.
  • Removing dead or faded flower heads, you will see an increase in flower production. We call this dead-heading.
  • Butterflies love Zinnia’s, and you’ll find an abundance of them attracted to your garden if you plant them outdoors.
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How to Get Rid of Algae in Hydroponics for Good!

Algae can cause major problems in hydroponics systems. It can build up and cling to any surface. This means there isn’t any system that can be safe from it once it gets a foothold. It sticks inside tubes, it can work its way into pumps, and it can bring a system to its knees.

Once it begins to decompose, it can bring with it a horrible odor. However, it is when you have a heavy infestation things get worse. This mass of algae can form a barrier against your growing mediums.

When this begins to happen, two significant things will happen. First is the precious nutrients are depleted from the system as the algae uses them itself to grow. Second, there is a severe drop in the dissolved oxygen in the system. This causes your plants to start suffocating, and means they are weaker to fight off any other pathogens.

What Is Algae and How Does it Get Into My Hydroponics System?

Algae is a simple, plant-like aquatic organism that can grow in just about any aquatic environment. Because they are so similar to plants, they require the same basis for growth; sunlight, water, and nutrients.

Algae can be an incredibly versatile and durable organism and can take hold wherever there is a minimal amount of these three basics. It’s because of their similar needs to the plants you are trying to grow in a hydroponics system that makes them difficult to prevent and address once they’ve arrived. You can’t starve them of their needs because your plants also need the same things.

In terms of how algae ever reaches your system in the first place, that is also explained by the versatility and durability of algae as an organism. While you might think that, your system is sterile, well contained and free from potential contamination sources during the setup process, algae can, and likely will, find a way into your system.

Algae gets into hydroponics systems through microscopic airborne spores. Because these spores can be so durable, it can be almost impossible to prevent them from getting into your hydroponics system. Many growers try to fathom how they get algae in their system when they have a sterile environment. The spores from algae can be carried by the wind, and it only takes one to latch onto your system. Growers themselves can even be a carrier of spores without realizing.

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Once in your system, algae finds the perfect conditions for growth – assuming you’ve set up a system that’s also perfect for the plants you’re meaning to grow! This is why algae can be so problematic. They are almost impossible to keep out of your system, and once they find a home in your system, they populate incredibly rapidly.

In this light, you should expect some level of algae growth within your system. Keeping a completely algae free hydroponics system is essentially impossible, and therefore, should not be the goal you’re aiming for.

By acknowledging that come amount of algae will be present, the focus of your efforts should be to prevent it from getting out of control and overtaking your system. While a healthy system can cope with small amounts of algae, as soon as the levels increase, it will be time to harvest your crops and take drastic action before starting another growing session.

By focusing your efforts on preventing algae growth getting out of hand, you can help to make sure that algae growth remains at an acceptable level. Any strategy for algae problems should be with control rather than complete prevention, because this can be nearly impossible to do.

How to Clean Algae Out of Your Hydroponics System

A lot of this will depend on the stage of your system, you may already have an infestation, or you are building a new system and want to prevent algae from occurring. Either way, it is better that you understand what causes algae, and how you can prevent it from taking hold.

Two things to note are that algae doesn’t grow on dry surfaces, and preventing as much light as possible from reaching your nutrient solution can help minimize the risk of an algae outbreak. All your channels and conduits will have covers, which prevents light from entering. Likewise, your media beds or pots can be covered to prevent light from hitting the surface.

Growers who face algae infestations may be tempted to turn to a commercially available algaecide. While these appear to be a good solution to control an algae problem, they are in fact of very little use.

An algaecide can help to control the blooms of algae, yet, if they are misused or overused, they can damage your plants delicate rooting systems. This is more the case if your plants are small, and have not long been planted into your system.

The worst thing with these commercial products is that once they are used, they weaken in the system, and then the algae just begins to grow again. This means you need more of the product, and you end up in a cycle that shows no end.

The first thing you’ll want to do is to assess the amount of algae in the system. If it seems to be a small amount, you need to determine where this is getting into your system. It could be some light finding its way into your reservoir, or into another part of your system.

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If it doesn’t become worse or affect your pump and air stones, you may be able to tackle the problem with some preventative measures until you come to the end of your growth cycle. At this stage, you can go through the following to give your system a thorough clean.

The following steps explain how to give your system a full clean. This can rid it of any traces of algae before you commence your next growing cycle.

System Clean and Sterilization

Because of how easy algae spores can be passed around via the air, it will be important to give your growing room a good clean as well as your system. There will be little benefit in cleaning your system to find you are up and running, and there are algae spores lurking on the walls or your lighting systems.

It will be your system, which is more important because it is this that is in direct contact with your plants. Growing medium and pots need their own cleaning, also if you are using clay pebbles, (Hydroton) be sure this doesn’t dry out and stays moist.

Step #1 Draining the System

Ridding your system of the old nutrient mix will be the first step. Some systems may not be using pumps; this would mean manually emptying your reservoir. If you have a recirculating system, then there are two ways to drain your tank.

If your tank has a drain valve, you can open this and let the water run out naturally. However, you will need a run off area, which is lower than your tank. If you are using the pump return method. Be sure to isolate all the electrics before removing the pump from the tank.

Remove the outlet pipe, and then connect the female connector onto the pump. You can now feed the outlet hose to your desired drain point. This will remover the water via the pump rather than naturally draining.

Once you reach the lowest point before the pump begins to run dry, you will need to turn it off. This method and the other will have a couple of inches of water remaining. Manually remove this using a sponge and a bucket.

Step #2 System Cleaning

Even though you are tackling an algae problem, these steps will be the same for a system clean after each harvest. This can be one way to be sure you have eliminated any traces of algae, pathogens or bacterial growth.

You can use two chemicals at this stage:

Food Grade Hydrogen Peroxide: This should be a 35% concentration. 3 milliliters (mls) for each gallon of water.

Unscented Bleach: The ratio of this should be 1:100. This would work out as 1.3 oz. to each gallon of water.

  1. Drain your system by either of the methods mentioned
  2. Remove pumps and air stones, these may require cleaning if algae growth reaches that far
  3. Remove any parts of your system which are hard to access
  4. Check for debris, broken roots and further algae growth
  5. With your cleaning solution of choice, use green scrubbing pads and wipe down all the areas where you see algae growth. Bottlebrushes can be used for hard to reach areas.
  6. Wipe clean and then assemble any system parts you dismantled
  7. Fill your system higher than usual as this covers the line where the algae was forming
  8. Add your sterilizing solution (bleach or hydrogen peroxide)
  9. Run your system for between 4 and 6 hours
  10. Scrubbing channels and conduits will flush this algae and debris back into your tank
  11. Drain your system and rinse with fresh water. Be sure to remove all the debris
  12. If using bleach, you need to triple flush your system
  13. Drain a final time and wipe down with clean towels
  14. You can turn on your lights as this can stop any algae starting to form and residual water

System Components

Although the algae may not be growing on your pumps or air stones, there may be traces on your growing medium and the pots. To clean all of these including pumps, the recommendation is to use hydrogen peroxide. You can though use a bleach bath to soak all of these small components. This will be a 1:1 mix, and you still need to carry out a triple rinse to remove all traces.

How to Prevent Algae from Growing in Your Hydroponics System

Algae growth in hydroponics systems is unavoidable to come extent. Anytime you’re working with nutrient rich water and sunlight, you’ll have ideal growing conditions for algae. As these are, the two main essentials needed in algae growth, and because you can’t avoid having a nutrient rich water solution, the best prevention method is to cut down on light exposure.

The best way to prevent out-of-control algae growth in your hydroponics system is to reduce your reservoir’s exposure to light as much as possible. This can be easier said than done, but there are a few ways to help with this.

  • Use Opaque or Solid Colored Materials
    One way to cut down on the potential light exposure is to use opaque and solid colored materials wherever possible. This will help prevent any light from penetrating into these parts of the system, thus reducing the potential for algae to photosynthesize and grow.
  • Cover All Exposed Water
    This step is similar to the previous step in that it’s predicated on prevented algae from ever getting started in the first place. Again, if algae can’t receive light to photosynthesize, it can’t grow and populate within your reservoir.

    There are a number of ways to cover your water, all of which depend on how your system is set up. For smaller rigs, it might be as simple as using a solid colored material to build your plant supports into. In larger systems, you may need to fashion a sort of tarp or plastic cover with holes cut out for your plants to grow through, but that covers all other areas.

Alternative Options for Preventing Algae Growth

While the most effective way to prevent algae growth in a hydroponics system is to cut off any potential light sources, there are a few alternative measures that growers can take to avoid this nuisance. These options vary in their effectiveness but can have good results when applied properly.

  • UVC Light
    One method for this is to install a UVC light in your water filtration system. This light will help to kill and eliminate potential microorganisms, algae included, that could have found their way into your system. This can be costly, and they will need to be powered as long as your system is running. However, if you have serious problems with algae, a UVC light can be a good solution.
  • Grapefruit Seed Extract
    Some studies have found that grapefruit seed extract in the correct dosages can be an effective measure for killing and preventing algae growth. Grapefruit seed extract is a powerful anti-parasitical, anti-bacterial and anti-fungal compound. When used in low doses, it has been proven to very very effective in hydroponic systems while not being toxic to plants. The dosage recommendations will be around 5 to 10 drops per gallon of water in your system. This can be sufficient to prevent algae growing.
  • Barley Straw Rafts
    This solution should only be considered if growing on a large scale in a larger rig but has also shown effectiveness in fighting algae growth. Studies have found that the aerobic decomposition of barley straw release a chemical solution which inhibits algae growth. Again, this is a slower process, and isn’t ideal for smaller growers. You do need to be sure there is lots of dissolved oxygen in your water so only aerobic decomposition takes place. You can now purchase liquid barley straw extracts for use in the prevention of algae growth, but you do need to be careful of the amount of algae death as this can reduce the amount of dissolved oxygen.

No matter which method you use to clean and control the growth of algae, in your hydroponic system, there is nothing better for prevention that limiting light exposure onto your nutrient mixture.

Algae and pH Fluctuations

One area not mentioned is how algae growth can have a severe impact on your pH levels. While methods such as ebb and flow systems are more prone to algae growth, there isn’t one system that will be free from it forming.

Algae is resilient and as soon as the conditions re almost ideal, it will get a foothold and can lead to issues. In this case, pH fluctuations. Algae uses carbon dioxide in the same way as plants, this coupled with nutrients and light help produce photosynthesis during daylight hours. As this period nears its end, the pH will usually be at its peak.

During night hours, the opposite happens. It is here the algae consumes dissolved oxygen from the water to release carbon dioxide. This itself is released back into the water via respiration. The problem here is this carbon dioxide will create carbonic acid, and as such, it causes a drop in pH levels.

These swings do nothing but cause more problems as they progress. Plants can end up suffering from nutrient lockout, or they can slowly drown through lack of oxygen in the water.


Because there is no way you can eliminate the chances of algae from forming, it is better to expect its presence and take precautions to limits its exposure. By following all the above, you stand the best chance of being algae free, and having a system, which performs at, is best.

Prevention is the best medicine because if nothing else, it will save hours of cleaning to eliminate the same problem repeatedly.

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Learn How to Keep pH Stable in Hydroponics

When new growers first start a hydroponic system, they often hear terms that sound confusing. One of the hardest to fathom is the pH, while you may not fully understand it in the beginning, it is something, which in theory can be learned quickly.

In summary, to keep pH levels stable, it can take a few steps and a little effort from the grower. These are the key areas you need to understand.

  • Delivering the right supply of water
  • Performing water treatment methods in response to the tested levels
  • Understanding how the addition of nutrients can affect pH levels.
  • Understanding what pH levels your given plants require

When you begin to understand what pH levels are, you quickly learn that they will never remain stable on their own accord. There are too many variables, and many external influences that will change the pH level.

It does take effort to monitor and alter your systems pH; however, this isn’t hard once you understand the core principles.

To know what pH means to your plants, and how it can affect their growth is the first area you need to understand. After looking at what pH is, we will see how it affects your system, and how you can maintain the correct levels.

What is pH?

First, up, there is a scale that runs from zero to fourteen. Every liquid will have a different reading against this scale. Plain water as an example has different pH levels depending on the source. Plain water from the faucet will have a different pH to the water in your system; this is because in many cases it is better not to use faucet water when possible.

This scale has zero, which is the most acidic, this runs up to the top (number fourteen), and this is the most alkaline. Most living things like a middle of the road balance, so this is around 7. Not only is this a good starting pH for most plants to thrive, but it is also the right level for the human body.

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For plants to thrive at their best, they do favor pH levels, which sit around 5.5 to 6.5. Nevertheless, there are some plants and vegetables which like to go the other side of neutral to a pH of 8. Alkaline substances are soluble salts made up of potassium and sodium carbonate. Alkaline is the scale of the alkali within the solution.

When you have favorable pH levels in your system, this enables your plants to take up all the micro and macronutrients through the root systems. Add to this, you see faster growth in your plants because they have an increased intake of NPK (Nitrogen, Phosphorous and Potassium).

To go further in depth on this matter, you can head over to the pH levels Wikipedia page for a detailed breakdown of what these levels mean. This may appear interesting, yet it reaches a little outside what you need to know as a grower.

Acidic Solutions pH Alkaline Solution pH
Battery acid 1.0 Blood 7.35 – 7.45
Gastric acid 2.0 Hair shampoo 8.0
Lemon juice 2.4 Sea water 8.0
Cola 2.5 Permanent wave 8.5 – 9.2
Oxygenated water 2.5 – 3.0 Hand soap 9.0 – 10.0
Vinegar 3.0 Hair dye 9.5 – 10.5
Orange or apple juice 3.0 Magic straight 11.5
Beer 4.5 Household ammonia 11.5
Coffee 5.0 Household bleach 12.3
Milk 6.6 Household lye 13.5
Pure water 7.0 Drain cleaner 14

One thing, which is worthy to note, the closer you get to each end of the scale, and the liquids will burn. It doesn’t matter if it is acidic, or alkaline, so you will need to take caution when dealing with any pH level treatments.

Why pH Levels are Important in Hydroponic Systems?

We have seen when pH levels are outside the ideal range for your plants, they run the risk of not absorbing enough nutrients to help them grow. On top of this, it also helps you understand how soluble the salts are in your nutrient mixture.

Every mineral has a different tolerance when it comes to the respective pH level. As a rule of thumb, plants need high amounts of macronutrients. If the pH level is too high or too low, then these become immobile, and it is this that restricts their uptake, and leads to nutrient deficiencies.

Micronutrients on the other hand are required in smaller doses. These will be affected on either end of the pH scale. Once your pH is too low, then this means your plants can absorb too many as they are highly soluble. This doesn’t lead to nutrient deficiency; it actually leads to a solution that is toxic to your plants. If you go to a pH that is too high, then you will see a deficiency in micronutrients.

One of the first signs you need to be aware of is young foliage, which is yellowing or pale in color.

In order to keep the pH levels balanced in your hydroponic system, first, you really need to understand the elements that will affect the pH levels.

Growing Medium

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Almost everything can affect your pH level in your system. One of the most significant areas will be your growing medium. A good example being calcareous rock, this will release magnesium and calcium into your solution. As soon as they leech into your water, you will need to adjust. Luckily, this isn’t a common growing medium.

Coco coir is very popular, and this can affect pH as they contain sodium chloride. Because of this, this needs to be soaked thoroughly to wash out any residual contaminants.

One other common growing medium is perlite. The pH of this is between 6 – 8, this means it can be added with no significant pH swings in either direction. Rockwool is another favorite and has a pH of between 7 – 8.5. This does require washing before use and an adjustment of the pH once it is in your system


There is a lot to learn about solution temperatures, so without going into too much detail hydroponic solutions should be around 65 to 80 degrees Fahrenheit. If it gets much warmer than this, water starts to evaporate faster than the mineral salts.

One this happens, these begin clinging to the side of your reservoir, and thus increase nutrient to water ratio. You can also find that systems, which have smaller reservoirs, suffer more than a larger reservoir. Depending the region you live, you may require either a water heater, or a water cooler to keep your mix at the ideal temperatures.

Plain Water

Hydroponic systems need a sterile environment to function at their best. Water from the faucet isn’t recommended because of the amount of treatment it has been through. Different regions can have hard or soft water, so the base pH will never be standard.

It is a recommendation to use distilled or reverse osmosis water when possible. If this isn’t readily available, you can purchase these reverse osmosis kits which sit in your plumbing system. While these can seem to be a small investment, they can pay for themselves over time.

Here is an example of a reverse osmosis filter system. It can deliver pH neutral water for drinking, as well as for your hydroponic system.

Setting Up Your Hydroponic System Correctly

Now you understand all the reasons that pH levels are important to your hydroponic system, and the plants you’re growing, it’s time to test your pH levels and get your hydroponic system running before introducing plants into the environment.

If you are still researching, the following will still apply because pH testing isn’t a one shot thing. In the beginning, you can be doing this on a daily basis until you understand how your system works. To test your pH levels, there are various ways you can do this.

By the use of litmus strips, or digital testers, you can quickly find whether you need to adjust levels up or down.

One thing to note here is that some of the better hydroponic nutrients come with a pH buffer. This takes away any sudden level change to your plants. While you still need to adjust, the extent of what you do will be minimized.

Litmus Strips

Litmus strips are one of the quickest and simplest ways to test the pH in your system. Although they are easy to keep on hand, you shouldn’t rely on them without another means of measuring in place. The way these works is the paper contains a dye, which is sensitive to any liquid it comes into contact with.

To test your system, take a sample of your water in a sterile container. Dip one of the strips into this wait until the color changes. Once there are no more changes, you compare this against a chart, which comes with the litmus pH testing kit.

You may find some of the colors can be hard to distinguish from each other, so trying to guess which one it is, isn’t the best way to be safe. Many plants may not bother with this little difference, yet this half a reading in either direction can affect plants that require a tight tolerance.

You can also find liquid testing kits, which work in the same way. With these, you add the dye to your sample, and then once the sample finishes changing color, you compare this against your chart.

Hydroponic pH Pens

The most reliable option works out the most expensive, however, this is not overly expensive, and it can last much longer than your litmus testing kits. On top of this, you will have a digital readout, so there is no way to make a mistake.

One of the common designs is the digital pH pen. Once you place the nib in your water sample, you get an exact reading, which is precise. One downside with these is that over time, the readings may fluctuate, this means your pH pen requires calibration. If you perform lots of testing, this can be a weekly exercise.

We have written a complete guide to testing the pH of your water, we highly recommend understanding the full process to stop your plants wilting.

Continual Water Treatment and pH Balancing

Now you see the equipment you need to use to test your nutrient solution; we will look at how the varying hydroponic systems can have varying pH levels. One of the more straightforward are NFT (Nutrient Film Techniques) as your solution is in direct contact with the plants root systems.

Media based systems can have readings that vary one way or the other. It is for this reason; you need to take two separate readings. The first needs to be taken from your nutrient reservoir, and the leachate, which is the chemical runoff.

This is necessary because you will have different readings before and after the rooting system. This may not vary too much if you have smaller plants, yet larger plans will mean the variance is much higher.

When adjusting your solution pH levels, the base adjustments in the reservoir need to be adjusted to the readings you obtain from the readings you come up with from the runoff solution. The reason this needs doing is that your plant roots will be facing the pH levels in the solution, which passes them, and not the solution in the reservoir.

Adjusting Your Hydroponic pH Levels

Your pH levels rise and fall for all manner of reasons. Luckily, we have seen how easy it is to fix some of these. We also saw that your nutrients would come with pH buffers when you purchase them from reputable suppliers.

These buffers are a great way to prevent spikes or drops which may shock your plants. Aside from this, these suppliers also offer chemicals that you can use to raise or lower your pH levels. One of the more frequently used comes from General Hydroponics. These have pH UP and pH down you can purchase. Because of the pH sensitivity, you do need to follow recommended doses and take separate readings, in case you need to adjust again.

The aim when making your adjustments is to make sure there is no nutrient lockout. This takes daily readings to be sure your pH level is going in the right direction

When you come to make your adjustments, there are only a few steps you need to take to make these adjustments. The main thing is to be observant of what your readings are.

  1. Take your first sample and then a reading Depending on the result you obtain, all you have to do is add between 1-2 ml of the pH Up or pH Down solution for each gallon of water you have in your reservoir.
  2. Once you add this, stir your solution with a clean implement and wait a minimum of 30-minutes so the solution can run around your system. At this point, you can take your next reading.
  3. You need to repeat these steps as required until you reach the required level. Never be tempted to add more of either chemical to reach the results faster. This will, shock your plants because you may swing too far in either direction.

When you add new nutrients, they will change your pH levels, which is why you will always need to do a new test once these have been added to the new reservoir. Other than that, it is recommended to run your tests more or less the same time each day. There are a number of natural approaches to tuning your pH if you have no pH Up or pH Down.

This is a very short-term solution and you should only use this if it is absolutely essential. Either white vinegar or citric acid may be used to reduce the pH, whereas baking soda is used to raise your pH levels. When doing this, you will need to know how much of a change there is for the amount you add.

Maintaining pH Level Recap

To summarize all the above, here is a quick recap of everything we have shown. Following these, you can maintain your pH levels and have plants that are continually thriving.

  • Check your levels daily until you get to know your system. When you see how things are running, you can reduce your testing to 2 or 3 times per week.
  • Even if you can’t afford the best testing kit there is, you should look for the best one you can afford. Litmus tests are handy to use, yet when you attempt to adjust your readings a few times, these are not as quick as pH pens.
  • If you spot your pH, levels fall between 5.8 – 6.5. You should not be tempted to make any adjustments. This reading is ideal for most plants that you may be growing.
  • Solutions which have a high pH need adjusting with pH Down.
  • Levels, which are low, need adjusting with pH UP.
  • Keep records of your testing and how much solution you add into your reservoir.

Overdosing with pH adjusters or nutrients is highly harmful to plants. On top of this, if you have a solution that drops in your reservoir, the pH change at the same time. Even topping up with water will have an effect, so be sure all your readings are when you have a full tank.

Growers who understand what their plants need, and how to adjust to keep them healthy will have some of the best crops when harvest arrives. Any grower who thinks this isn’t important may face a catastrophe.

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How to Recycle Hydroponic Water: A Beginner’s Guide

There are so many options to support a thriving garden and hydroponics is one of the most recent systems I’ve read about. I’ve read that recycling hydroponic water can help save me money.

How to recycle hydroponic water: a beginner’s guide: Recycling water is a relatively simple process but can cost quite a bit of money between the initial investment and maintenance cost. You can use one of three main systems to recycle hydroponic water. Here’s a look:

  • Pasteurization
  • Ozone Sterilization
  • UV Disinfection

If these systems sound as foreign to you as they do to me, I’m here to help. Take a look at a beginner’s guide on how to recycle hydroponic water.

The Importance of Cleaning Recycled Hydroponic Water

You’ll see many benefits from hydroponic growing but one thing you’ll quickly realize is that the system produces huge amounts of wastewater. Rather than just toss the wastewater (which is a bad idea anyway), many growers are starting to recycle their hydroponic water.

Recycling hydroponic water is a great idea. It cuts down on your water use and cost and helps prevent damage to the environment. That’s right, what’s good for your plants may not be good for the environment.

The nutrients that help your plants grown quicker than normal and produce more fruit can negatively affect the environment and groundwater that is turned into drinking water for humans.

Hydroponic solution is normally made up of at least a few of these nutrients:

  • Nitrogen
  • Phosphorous
  • Potassium
  • Calcium
  • Magnesium
  • Sulfur
  • Iron
  • Boron
  • Copper
  • Manganese
  • Zinc
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(If you haven’t read our articles about DIY nutrient solutions or if nutrients can go bad check them out)

Certain studies have found high levels of nitrogen and phosphorous in hydroponic water that was dumped. Those two nutrients, along with sunlight and slow-moving water, are what create algae blooms.

Algae blooms have a number of negative effects on our environment. Here are the four main issues:

  • Algae blooms produce dangerous toxins that can sicken or even kill animals or people that come in contact with them
  • Algae blooms create dead zones in the water. A dead zone is an area with low oxygen levels (low oxygen levels can lead to root rot). Eventually all the animals in the “dead zone” die.
  • Consumers see higher treatment costs for drinking water affected by algae blooms
  • Algae blooms hurt industries that depend on clean water.

While I’m sure you’re concerned about the effects on the environment, the other appealing reason to recycle your hydroponic water is the cost savings to you by not using as much water.

Plants grown in hydroponics already use 80 to 90 percent less water than standard plants grown in soil because the solution passes over the plants’ roots many times before you have to get rid of it.

Before you start reusing and recycling your hydroponic water, it’s important to clean and sterilize the water. It can carry bacteria, viruses, and other diseases. If you put this back into your system, you could potentially infect and damage your plants.

As I mentioned before, there are three main systems used for sterilizing your hydroponic water:

  • Pasteurization
  • Ozonation
  • UV Disinfection

There are pros and cons to each system. Take a look at this table comparing the systems.

System Pros Cons
Pasteurization No need to pre-filter water, minimizes buildup of minerals in water Causes mineral buildup in pasteurization machine
Ozonation Most effective form to sterilize water, environmentally friendly, prevents disease Expensive, highly corrosive- can damage equipment
UV Disinfection Highly effective, chemical-free, cost-effective Doesn’t remove heavy metals, salts, or chlorine

Now, that you’ve taken a brief look at the pros and cons of each system, let’s dive in and take a deeper look to figure out which system might be best for you.


You might be familiar with the term pasteurization because it’s used in many of our everyday foods: milk, juices, egg whites, etc.

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The process of pasteurization kills harmful, pathogenic bacteria. Removing the bacteria prevents diseases such as typhoid fever, tuberculosis, scarlet fever, polio, and dysentery.

Of course, these diseases aren’t an issue for your plants, but using pasteurization on your hydroponic water removes other bacteria that might harm your plants.

So, how does pasteurization work? Take a look at this process.

  1. The used water is run through a 50-70 micron filter reducing the pH to 4.5 (learn how to monitor your water pH levels)
  2. The adjusted solution is pumped to the first heat exchanger
  3. This heat exchanger preheats the water while recovering heat from the sterilized solution
  4. Sterilized solution leaves the first heat exchanger and is pumped into the second heat exchanger
  5. An external heat source heats the nutrient solution to a certain temperature, ideally at least 203 degrees Fahrenheit
  6. The nutrient solution is exposed to the high temp for at least 30 seconds
  7. The sterilized solution is returned to the first heat exchanger to cool

It sounds complicated but you don’t actually have to do much.

As I showed in the table above, using pasteurization to sterilize your water prevents excessive mineral build up in the water, but can lead to mineral build up in the machine. This can decrease how well your machine works.

Your best bet to find a pasteurization machine for recycling your hydroponic water is in a specialty garden store or catalog.


Ozonation uses ozone to sterilize the water. Ozone is just oxygen with three molecules. During ozonation, the water is infused with ozone. The gas ozone is created by ozone generators in your grow room.

There are two types of ozone generators: corona discharge and ultraviolet. They work by splitting oxygen molecules into individual oxygen atoms. The atoms then bind to oxygen molecules creating ozone.

Here are all the steps to complete ozonation.

  1. The water is filtered with a 50-70 micron filter.
  2. Check the pH level of the water to make sure it’s between 4.0 and 4.5. This gives you the best results.
  3. Your hydroponic water is pumped into the ozone generator.
  4. The amount of ozone and length of sterilization depends on the level of nutrients in your water.

The benefits of ozonation as shown above are that it’s very effective and environmentally friendly. The downside is that ozonation can be costly and it’s highly corrosive so you have to be careful when dealing with it.

UV Disinfection

One of the final methods of high tech sterilization is ultraviolet or UV disinfection. UV radiation is part of the electromagnetic spectrum.

There are three types of UV radiation and they’re defined by frequency and wavelength. The best type of UV radiation for disinfecting your hydroponic water is UV-C. This type has the shortest wavelength and the highest energy.

UV-C radiation very efficiently kills bacteria, fungi, and viruses. Based on various studies, it looks like 250 millijoules per cubic centimeter is the appropriate radiation dose to totally disinfect the water.

Here’s a look at how UV disinfection works.

  1. Pour the water into a disinfection unit.
  2. The hydroponic water passes through a radiation chamber.
  3. High pressure UV lamps contained in a quartz tube in the chamber disinfect the water.
  4. A computer controls the process. If the UV dose is too low, the process is blocked and the water is returned to a drain water tank.

UV disinfection is pretty cost-effective compared to pasteurization and ozonation. It’s also natural. The only downside is that it doesn’t neutralize organics, chemical contaminants, or inorganic compounds in the water. This means it doesn’t remove heavy metals, salts, or chlorine that may have built up in the water.

Whatever sterilization method you choose, it’s essential to recycling your hydroponic water. You have to kill any destructive microorganisms that may have grown during the previous cycle.

Other Possibilities for Recycling Hydroponic Water

If the recycling options we talked about above sound like they’re out of your financial abilities or too much of a time commitment right now, you can consider just using the water on your other plants.

It’s important, though, to check the levels of the nutrients in your hydroponic water to make sure they’re not too high. If they’re too high, don’t use the water on any plants that are directly in the ground because the nutrients could affect your local water table.

A good way to check the nutrient levels in your hydroponic water is to check the potential (pH) and electrical conductivity (EC) levels. If these are within a certain range, your hydroponic water should be safe.

A good pH level is between 5.5 and 6.5. An appropriate range for EC levels is 1.2 to 2.0. You can read our full guide to EC and why you should monitor it here.

Plants in one study even showed better growth using recycled hydroponic water than those without. Here a look at the plants that performed well:

  • Tomatoes
  • Red peppers
  • Cabbage
  • Melons
  • Cucumbers

There are a few other options for recycling your hydroponic water that you may hear talked about. While they have some effectiveness, they’re not recommended because none of them completely disinfect the water.

These are the other methods you might hear about:

  • Ultra-filtration
  • Hydrogen Peroxide
  • Iodine


Ultra-filtration is also known as membrane filtration. It includes the process of reverse osmosis. These types of filters have more porous membranes that allow solids, bacteria, and other large particles to be filtered out.

The main problem with this process is that the pores in the filter tend to clog making it an unreliable choice. The other problem is that the filters also remove fertilizer salts from the water, which are helpful for plant growth.

Hydrogen peroxide

Hydrogen peroxide works in much the same way as ozone does but it’s weaker. Because of this, it’s effective against fungi and viruses but not so much against bacteria.

If you recycle your hydroponic water but it’s not totally disinfected from the bacteria, you’re asking for trouble as soon as your plants touch the water again.

Levels of hydrogen peroxide that are too high can also damage your plant if they’re not neutralized before you return the nutrient solution to your plants.


You may be familiar with iodine because it’s used in drinking water to kill human viruses, but it doesn’t actually kill horticulture viruses. This means that it’s not effective for disinfecting your hydroponic water.

Recycling hydroponic water back into your other plants still ends up saving you money and might even give you more plant growth.

A Key to Successfully Recycling Hydroponic Water

You can set yourself up for success in recycling your hydroponic water right from the start. Keeping your nutrient solution levels under control is key to extending the life of your hydroponic water before you even need to recycle it.

The best way to keep the nutrient level under control is to make sure you’re only putting in clean water. This means when the water level dips, refresh it with totally clean water. If you don’t, trace elements in the water will eventually accumulate to toxic levels.

If you were thinking you have to dump your entire nutrient solution any time the level drops, it’s time to do a little research. You can actually refresh the nutrient solution with clean water until you’ve replaced half of your system’s water capacity.

For example, if you have your hydroponic system has a 20-gallon water capacity, you don’t need to empty all of the water until you’ve replaced 10 gallons. This means that keeping meticulous notes is super important so that you do know when it’s time to recycle your water.

Rain water, city water, and well water are all possible options for clean water to replace water that is used. It’s always still important to do a water analysis, especially on city water and well water, to ensure that all elements are within a reasonable level.

Cities sometimes have to “shock” water with large amounts of chlorine to get rid of some sort of biological contamination. These high levels of chlorine can harm your plants.

Well water sometimes has very high levels of bicarbonates. Phosphoric acid is used to lower these levels, but sometimes a byproduct of the treatments is calcium phosphate. This can clog drip lines and submersible pumps and affect your nutrient solution.

You’ll quickly learn a key to success in hydroponics is very routinely analyzing the mineral levels in the water.

What Exactly is Hydroponics?

If you’re looking to recycle hydroponic water, I’m assuming you’re already aware of the ways of hydroponics. If not, though, I can give you a brief explanation so you know what you’re getting into.

Hydroponics is a way of growing plants in a water-based solution rich in nutrients. This type of growing doesn’t use soil, but an inert medium instead. An inert medium is one that doesn’t have any nutrients. Here’s a look at some possibilities:

  • Perlite
  • Rockwool
  • Clay pellets
  • Peat moss
  • Vermiculite

Hydroponics works when the plant roots come in direct contact with the nutrient solution.

There are quite a few benefits to hydroponics. One of the main ones is that your plants grow quicker, up to 25-percent quicker. They’re also more productive, sometimes producing up to 30-percent more than plants grown only in soil.

The quicker growth and production happens because plants can access nutrients quicker and expend less energy. Because of this, they don’t have to grow a super big root system and can instead focus on growing quicker above the roots.

Along with the advantages of positive growth and production, hydroponic gardens do have some downsides. Here’s a look at some of them:

  • Initial cost
  • Time and commitment
  • Technical knowledge
  • Threat of power failure

Initial cost

You’ll spend some money upfront to get your hydroponic system up and going. You need containers, light, a pump, a timer, one of the growing mediums mentioned above, and nutrients.

Try to keep your initial investment under a few hundred dollars if you just have a small home garden. The good news is after your initial investment, your only costs are water and lighting.

Time and commitment

If you’re looking into hydroponics, you’re probably willing to invest some time in your garden. If not, hydroponics may not be the best choice for you.

You can’t just set up your hydroponic system and leave it. It requires monitoring the water level and the nutrients and adjusting the levels as needed. Unlike using soil, if the levels are off, the plants won’t just adjust to the changes, they’ll die.

You may eventually be able to automate your hydroponic system, but not initially. First, you need to get a feel for the needs of your plants.

Technical Knowledge

A hydroponic system isn’t just a simple pot with some soil. It requires putting the system together, figuring out which plants grow best with which nutrients, and making changes as needed. The elements are crucial to your garden’s success.

Threat of power failure

Finally, your whole system runs on electricity. This means if there is a power outage of any length, your system stops running. If the power doesn’t come back on within a couple hours, your plants will dry out and die.

A back up power source and a plan for if the power goes out helps minimize this disadvantage.

Despite the disadvantages, it’s worth giving hydroponics a shot. Eventually, you’ll save money and a great way to do that is by recycling your hydroponic water like we talked about above.

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