How to Make Liquid Fertilizer for Hydroponics

Hydroponics is a great way to grow plants at home. New growers can quickly recover initial build costs, and their power bills are not as bad as they initially anticipated. One cost they may wish was cheaper, or there were alternatives is the price of liquid fertilizer.

Because these mainly comprise of water, shipping can be more expensive, and they don’t last very long once they are in use. This repeat purchasing can make a big hole in anyone’s budget.

However, it is possible to make your liquid fertilizer, so you save some money! You do need to be sure you include all the required nutrients that are in the store-bought alternatives so plants can thrive without deficiencies.

How do you make liquid fertilizer for your hydroponic system? The quickest way is to follow these simple steps:

  1. Place one gallon of organic compost or a pound of worms castings into a large bucket with a lid
  2. Stir in water and agitate the contents well
  3. Aerate the mixture with an aquarium air pump
  4. Set the bucket aside for three days. Stir every day

The strained liquid is your fertilizer and is ready to put into your hydroponics system. You can use animal or plant byproducts to make a liquid fertilizer as well.

Here we will show you all you need to know about making liquid fertilizer that is suitable for use in a hydroponic system.

Why is it Possible to Make Liquid Fertilizer?

The nutrient mixes and the boosters and deficiency formulas are straightforward to make. New growers may wonder why individuals like them can do something so simple without harming their plants.

There is one primary reason for this, and that is that plants may be fussy about the nutrients they receive and the ones they don’t. However, they don’t care where they come from.

Plants don’t even care if your liquid fertilizers are organic or man-made. They just want the nutrients in the right amounts.

When plants grow in the soil, the plants will be able to absorb anything that they want, but in hydroponic systems, the grower has to make sure all these nutrients will be available in the proper amounts?

For each plant, macronutrients and micronutrients are necessary for flourishing. However, the proportions of these required are very different in the types of crops you will be growing. There are several variations in these home-made formulations, so making one batch of one kind can deliver a very different proportion to that of the next.

You can create a liquid fertilizer solution from nutrient salts, and these may be easier because you can adjust your blend to the weight of the salts you add. If you do use these, you must maintain their freshness and dryness, since the moisture absorbed will affect their weight.

The other thing to be aware of is that you need measuring spoons, a decent set of scales as well as rubber gloves when mixing any commercial formulations. The crystalline compounds can either burn or have another kind of reaction on the skin.

Finally, the nutrients you buy will usually have the inclusion of additional pH buffers. Since you are in the process of making your own, you are going to need a digital pH pen and solutions of pH UP and pH Down.

While measuring your pH levels, you can see your EC levels may be out of synchronization, so one other device you may also need is an EC meter.

How to Make Different Kinds of Liquid Fertilizer

There are multiple ways to make liquid fertilizer. Some methods you may have close to hand, or you can decide to purchase which components you need and begin making your own.

In the following sections will be all the formulas and steps you require to make a few different liquid fertilizers for your hydroponic garden.

Necessary tools for making Liquid Fertilizer:

  1. 5-gallon bucket
  2. Aquarium air pump
  3. Disposable filters
  4. Measuring spoons

Compost Tea/Worm Tea

Ingredients

  • Water for mixing – don’t use faucet water. Use rainwater or aquarium water if you have access.
  • 1 gallon of compost or 1 pound of worm castings
  • Aquarium air pump for mixture aeration
  • Disposable filters for straining the compost or casings

Directions:

  1. Place the compost or the worm castings into a large bucket
  2. Fill the bucket with water and mix well, so everything is combined
  3. Set the bucket aside for approximately three days, however, keep the bucket out of direct sunlight so the slurry will not evaporate.
  4. Add an air stone and run while the mixture ferments for this period. The aeration breaks up the matter and helps nutrients spread through the liquid mixture.
  5. Stir the contents daily to make sure the nutrients spread through the mixture.
  6. Run the resulting liquid through disposable filters to filter out all the solids. You can use the resulting liquids to add to your reservoir for fertilizer.

You can continue making this in batches as you will require about half-gallon for every 50-gallons of water in your reservoir.

Sea and Animal Byproduct Formulation

Ingredients

  • 1 gallon of water as a base for the mix.
  • 1 ½ teaspoon of fish emulsion for nutrients
  • 1 ½ teaspoon of seaweed extract for nutrients
  • 1 tablespoon of blood meal for nutrients

Directions:

  1. Add 1 gallon of water to a large bucket
  2. Add 1 1/2 teaspoons of fish emulsion
  3. Add 1 1/2 teaspoons of seaweed extract (You can use dried seaweed if not roasted)
  4. Add one tablespoon of blood meal as extra nutrients to promote plant growth.
  5. Stir well and use it as fertilizer for your plants.

You still need to filter this in case there are any large lumps in the blood meal. Also, if you use seaweed, you will need to let this steep a while before use. Tie it in a cheesecloth and let it sit before straining.

Fertilizer-Water Mix

Ingredients:

  • 3 gallons of water
  • 2 teaspoons of nitrogen fertilizer
  • 2 teaspoons of phosphorus fertilizer
  • 2 teaspoons of potassium fertilizer
  • 3 tablespoons of Epsom salt, unscented

Directions:

  1. Pour all the gallons of water into a large 5-gallon bucket (use rainwater or pond or aquarium water)
  2. Add the three fertilizers into the bucket and make sure there are no lumps
  3. Be sure the fertilizer contains both macronutrients and trace elements, such as copper, zinc, and molybdenum.
  4. Add Epsom salts to the water to provide magnesium sulfate. This is one of the more essential steps.
  5. Mix the solution until everything dissolves.  
  6. You can add this to your system when you next flush and are ready to mix your new batch.

Before adding, like the other formulations, it will require filtering before use. Any lumps can block your system unless you are not using a water pump.

There are many other formulations of fertilizers you can make, yet these above are proven to be beneficial to any system.

Liquid Fertilizer Growth Boosters

While the above formulations can help save some money in comparison to purchasing hydroponics nutrients, there are times when plants can do with that little extra boost.

This can be if they begin showing signs of deficiency, or the plants are at a different stage of their growth. The following liquid fertilizer boosters are straightforward to make and can be just the thing to help your plants when they need a little extra.

Deficiency Boosters

Calcium Deficiency

Plants that show signs of calcium deficiency can benefit from this simple addition.

Crush six washed eggshells in a pestle and mortar or a blender. Add to 1 1/2 liters of water with a few drops of hydrochloric acid. Let stand for 24-hours before filtering out the shells. Test the liquid to make sure it has a pH of around 5.

In the growth stage, you can use it with nitrogen-rich fertilizers. In the flowering stage, you can use it with fertilizers high in potassium and phosphorus.

Potassium Boosters

In the flowering stage, this can increase growth by 20%. This can help plants use sugars, carbs, and starches they absorb.

To make this, boil three to four banana skins in a liter of water. Add a little sugar or even better molasses. Let cool and use a few drops as needed.

Growth Enhancers

Coffee Ground Booster

Add used coffee grounds to water and let them soak for 24-hours. Filter and add the liquid to your tank during the growth stage. The bacteria that develop on the waste coffee grounds contain 2% nitrogen as well as many other organic nutrients.

Root Growth with Bean Tea

Beans and lentils are full of compounds called Auxins. These are fantastic for root growth along with stems and leaves as they reach up toward your grow lights. All you need to do is soak beans in water until they are hydrated. At this stage, blend them into a paste.

Strain this with a fine cloth. This is perfect for cuttings or seedlings to promote root growth.

Multipurpose Fertilizer

Take one small spoonful of Brewer’s Yeast and add it to a literof water. When this dissolves, it will produce potassium and phosphorus-rich liquid fertilizer. You can add this at any stage of growth for your plants.

Using Homemade Liquid Fertilizers

One of the most significant problems with making your own is that each time, you can end up with a different degree of nutrients in each batch.

However, when the blends are too high in the concentration of some nutrients. Your plants will be unable to absorb sufficient water. The salts will need to dilution, and if the nutrient mix is too high, your plants will start to shed water and not absorb it.

This results in the dehydration of your plants while the salts suck up the moisture from your plants. When you first start adjusting formulations, you need to do so with some restraint and caution. If you are wrong, you may destroy your entire crop.

Here are some common signs of nutrient deficiencies in your hydroponic plants.

  • Nitrogen: This produces plants with stunted growth that have more extensive root systems. Leaves may be smaller and light-colored. The growth will be slow.
  • Phosphorus: This will lead to stunted plants that have dark, discolored and dull leaves. Stems will be abnormally hard, and they will have a weak root system. Also, you will see a little branching.
  • Potassium: The older leaves will turn yellow and curl. Newer leaves fall off as they grow. The blossoms become dull, and the plant stems are soft and unable to offer full support.
  • Calcium: This makes the roots not develop much, and you have curly edges of the leaves.
  • Manganese: This leads to weak growth and poor flowering.

The only time you can be sure of the same levels is if you used powdered nutrients and mix them with water.

One other thing to be cautious of is that your plants don’t get any nutrient burn. Even with filtering, you can find your containers have sediment at the bottom. You need to be wary of this as it can quickly clog systems, especially your water pump.

Testing Your Liquid Fertilizers

It doesn’t matter which kind of nutrients you use for your system; you always need to check your system to make sure the TDS, PPM, and the pH levels are all in line.

The same issues can arise with homemade nutrients as they can with bought bottled nutrients, and the problems may manifest slightly different.

Here are the necessary procedural steps to test any nutrient mix you decide to make and add to your system. One thing you will note is the water is warm. This means it will be more in line with your system temperature when running, and it can help any powdered compounds to dissolve.

Test the pH of your water and the TDS/ PPM before you follow the next steps.

Your pH levels are sure to change when you add your compounds. Keep these initial readings because you will need them to find the precise concentration after you take your final reading.

With your measured out liquid fertilizer, add this to your reservoir and allow it to mix before you add any other booster fully.

Once you have added all your liquid fertilizers, let the solution stand until it sufficiently cools. With warm water, this should take around 2-hours. Once cooled, test the pH a second time and make a comparison with your first reading.

If it is outside the range that is right for your plants, you can adjust this with pH UP or Down until you reach the correct level.

You will need this second EC reading, as you will be diluting these mixtures at the time you are ready to add them to your tank.

While all the formulas for liquid fertilizer here don’t use many compounds, you can make liquid fertilizer from many of the same compounds as commercial farmers. These take much more experience, and you will need to adhere to the steps above.

Organic Liquid Fertilizers

Once growers begin making their liquid fertilizers, they may be thinking about making them organic. Most of the fertilizers above use compounds or elements that are already as good as organic. This again may make a grower feel better in themselves, yet their plants won’t care.

The issue with man-made and organic is that it can be challenging to reach the high levels of calcium and nitrogen needed to feed plants. The formulations provided here do their best, and there is a good chance you will need to make the boosters for supplemental feeding.

There is still a big debate on whether or not hydroponics can be organic at all. Using one of these, or any of the other liquid fertilizers is an excellent way to lean towards organic farming in time to make the switch when it best suits.

A good base for organic gardening is vermiculture, and with the worm castings, you can see this effective formulation pushes the meaning of organic to the limits.

Conclusion

These formulas may appear to be hard work for small amounts. However, the recipes can be scaled up so that you have sufficient liquid fertilizer for a couple of months. The upside with this is when you come to test because you will have a batch that is equal strength.

This doesn’t just make the formula easier to test, and it means your garden will be running the same with fewer fluctuations than ever before.

Making your own liquid fertilizer can seem to be hard work, yet the effort is well worth what you get out of it when your plants are blooming, and your crops have high yields just as if you were using regular store-bought manmade nutrients.

One thing which is often overlooked, when you make liquid fertilizer, is that you’re fruits and vegetables will taste better and won’t come with that hydroponic bitter taste some crops can.