Can You Grow Root Vegetables With Aquaponics?

With aquaponics, the majority of crops associated with this system tend to be of the leafy or flowery variety, with the harvestable part being on the upside of the grow bed, leaving the roots dangling beneath to absorb the life-sustaining nutrients. This tends to be the standard configuration and a very successful one at that.

Many growers are unaware that root vegetables can also be grown with aquaponics in just as healthy an environment, with equally impressive growing results.

Growing Root Vegetables With Aquaponics

Anyone who is immersed in the world of aquaculture can attest to the numerous benefits and the ease of growing herbs and leafy vegetables under this umbrella. For some, it is just a pleasurable pastime, while for others it is a blooming business, with flowers being one of the many beneficiaries of this system.

Perhaps looking to expand the business or wanting to broaden the variety of crops they cultivate, many farmers are looking at the possibility of adding root vegetables to their range of crops. But are all root vegetables compatible with the aquaponics way?

Root vegetables such as potatoes, beets, onions and carrots, for example, are top contenders for aquaponics, but certain changes have to be implemented to make these additions possible, with the growing process not being as straightforward as with leafy plants.

Carrots are probably the easiest vegetable to start with, not only because they can thrive in the aquaponics environment, but because of its hardiness and the colorful varieties available.

Apart from the classical orange variety, there are red, yellow, white and even purple carrots in the marketplace that, although not generally found in local supermarkets, are gaining in popularity. These uncommon varieties, Nantes, Danvers, Imperators and Chantenay, are just four types of carrots being incorporated in the root vegetable section by adventurous aquaponics farmers.

They can be a challenge Like all root vegetables in aquaponics there are initial challenges that need to be overcome, but if done correctly the successful harvests can be an eye-opener, and add different flavors and a splash of color onto the dinner plate.

Traditionally, all root vegetables are immersed in soil for absorbing the right amount of nutrients and water. With aquaponics, this soil has to be replaced by an alternative grow media to achieve a successful harvest.

Growing Carrots Aquaponically

Gravel and hydroton are the medium of choice for underground vegetables in aquaponics, either giving the roots something to grip onto for stability. An alternative to them is coco coir, a grow media that functions exceptionally well if the vegetables are to be potted in a cloth bag or a pot.

In this set-up, the nutrient-rich water from the fish tank will run through unimpeded, and the gentle compression effect from the coco noir encourages the root vegetables to grow to their standard recognizable shapes, rather than shapes that consumers consider to be deformed.

The fish selection also plays a defining role when deciding to go underground, and the most common fish in this type of aquaponics farm are tilapia and trout. These are ideal because many root vegetables can be grown in cooler climates and these fish thrive in cooler waters. Koi and goldfish can also be used if they are not be eaten.

Once the system has been set up and refined, and the correct fish selected for this endeavor, the crops can generally be harvested within two to three months. If there is sufficient space and if configured correctly from the outset, several other types of root vegetables can be grown within the same closed-circuit system.

To make the introduction of root vegetables into an established or brand-new aquaponics farm, there are full kits that can be purchased online or at gardening centers. These greatly simplify the process and reduce the time it takes to set up a fully functioning system.

These kits give detailed instructions on how and when to place the fish in the tanks, the ratio of fish required in relation to the number of root vegetables to be planted, and even when to increase the density of fish. All of this information takes the guesswork out of the installation process, eliminating costly mistakes that could otherwise be made.

Additional instructions on how long to wait after the set-up is completed before planting the root vegetables, the space required between the seedlings so growth is not inhibited, and even when to intersperse more seedlings among them, are invaluable to either an experienced grower or a complete newbie.

Residential Aquaponics Growers

Growing fresh fruits and vegetables has never been more fun and more accessible to residential growers owing to the simplification of the overall process.

Even those home gardeners living in cooler climates and with limited space can take advantage of aquaponics to grow all manner of vegetables indoors or in a shielded environment. The added ability to harvest crops at any seasonal time of the year increases the appeal, and the popularity of aquaponics continues to grow.

Once the mechanics have been mastered, the maintenance routine refined, then the expansion to include root vegetables is an easy step to take. There can be no doubt that in aquaponics healthier onions, potatoes, beets and carrots can be grown organically, and if they can all be accessible right from the bottom of your own garden…even better.

These ventures are sometimes started to save money, to grow healthier, more nutritious vegetables, in an environment that is not at the mercy of nature. What they morph into is a lifelong journey that either stays at the bottom of the garden or grows into a bigger business adventure.

The low maintenance aspect, the convenience, the harmonious nature of aquaponic farming itself, not only make this system sustainable for short-term harvests but ensures that it will continue to expand profitably into other farming categories not previously considered viable.

With the increasing demand worldwide for bolstering the food supply in impoverished countries, growing root vegetables with aquaponics could be a game-changer. Combine that with the fact that this farming method is constantly evolving and discovering better and faster ways to put a healthier meal on a plate, and it looks like aquaponics is finally getting to the root of the food problem.

Do You Need A Greenhouse For Aquaponics?

With aquaponics, the idea goal is to cultivate plants and crops in a controlled environment to achieve the best harvest at a faster rate than with traditional in-soil farming. This can be undertaken in either an indoor or an outdoor setting, where the results will be virtually identical.

The difference between the two will be in the amount of work required in an outdoor setting to combat the weather conditions, to control pests, to fight diseases, and even to protect the fish from harsh direct sunlight. Constant vigilance is required to offset these challenges, and that incurs more expenses and more stress.

A practical solution to balance the scales between starting an indoor or outdoor aquaponics farm is a greenhouse. It eliminates a host of challenges, affording protection against the elements while offering more control over the infrastructure.

Benefits Of A Greenhouse In Aquaponics

Practitioners of aquaponics understand the requirements of having a balanced system where the interdependent nature of the bio-sphere needs to flow seamlessly. Outdoors, there are numerous obstacles looming to create pitfalls that interrupt the cycle if not constantly brought under control.

With large commercial aquaponics farms, larger areas are needed to set up the system that most brick-and-mortar dwellings cannot house. The options are either to install the farm completely outdoors and overcome the challenges as they occur, or opt for constructing a greenhouse that can be customized to suit your personal circumstances.

Immediate advantages of a greenhouse stem from being able to create and nurture a micro-controlled enclosure where out-of-season crops can be cultivated.

Establishing this sheltered environment in a location where there is normally insufficient sunlight or heat can encourage the crops within to be grown to healthier fruition, and the fish reared in a protected underwater world, 

Surrounded by ever-changing seasons or just a naturally colder climate, that warmth can be provided by heat lamps, heat blowers, or some other source of artificial heating. To discharge any excess heat build-up, air vents can be installed to reduce overheating and regulate the temperature.

Conversely, if there is too much heat on the outside that, too, can be mitigated from the glass or plastic material that the greenhouse itself is composed of, or from cooling fans installed inside.

The prime objective of selecting an aquaponics greenhouse is to optimize the health and growth potential of the crops by creating ideal growing conditions and at the same time nurture the lives of the fish. One of the best ways to do that is to protect them from adverse weather fluctuations, pests, and diseases.

A greenhouse affords all of these benefits and is undoubtedly value for money even after the initial investment needed for extra equipment.

The Future Of Aquaponics Greenhouses

Recent studies have highlighted the benefits of utilizing greenhouses for aquaponic farming, not just for commercial growers but for personal ones as well. The flexibility in size availability makes it convenient for all types of environments and growers.

A popular type of greenhouse is euphemistically called the Growing Dome. It is classed as the best for a variety of reasons that include its diverse sustainable growing environment, its ability to foster hybrid conditions, and the inclusion of an above-the-ground year-round pond that is a perfect site to house a fish tank.

Within the Growing Dome greenhouse, there are generally two types of systems, Stand-Alone or Modular. Both have exceptional components that enhance the operational capabilities, but the choice of which is better boils down to the preference and objectives of the individual farmer. With either one, there is a possibility of having two income streams under one roof.

Traditionally in aquaponics, the fish are just a part of the biosphere with their waste being the main bi-product. In a Growing Dome, they can be harvested and sold on to create additional revenue, a major boon for growers both large and small.

This increase in profits will significantly attract more investors into this sector of greenhouse aquaponics farming, especially in colder climates where growing seasons are shorter and more challenging.

Tips For Using An Aquaponics Greenhouse

At the outset, it is important to take under consideration that there are two distinct lifeforms housed under one roof, each requiring different needs to survive and thrive. Crops require more sunlight and heat but can cope with slight fluctuations better compared to their fishy co-inhabitants

To maximize their potential, placing the grow beds in a position where they can take advantage of those two life-giving resources will result in heavier crops and increased production.

Fish, on the other hand, fall into the sun-dodging category, preferring to reside in the shade. If the tanks overheat due to incorrect placement in direct sunlight, the dissolved oxygen will decrease to dangerous levels and can risk the lives of the fish. A key point to remember is that it is a much more arduous task to cool down a fish tank than it is to heat one up.

Fortunately, there are greenhouses specifically manufactured for aquaponics, having an insulated south-facing wall to guard against direct sunlight, yet allowing in enough heat and light for plants and crops to flourish.

Employing the use of one of these greenhouses is a perfect choice to encourage year-round crop growing and harvesting. Its construction allows the warmer interior to be maintained at a stable temperature, while the north wall is ideal for placement of the fish tank, being as it is in a more shaded and cooler zone.

This level of strategic insulation saves on heating expenses and assists in minimizing unwanted temperature fluctuations.

There can be no denying that insulated greenhouses retain more heat than uninsulated ones. They are simply easier to manage in seasonal areas where the temperature can swing from one extreme to the next, from freezing cold to blazing hot.

In harsh winters, an uninsulated greenhouse can be unviable to run, the frozen temperatures on the outside mimicked on the inside, heating costs through the roof, and the effort required to keep the crops and the fish from freezing a constant battle of life and death.

Better Aquaponics Crops In A Greenhouse

Maximum productivity is the ultimate goal when deciding to erect a greenhouse over an aquaponics operation, not only from the choice of fish and crops that need to complement each other but also the layout of the farm itself.

With a brand-new greenhouse infrastructure, a blank canvass is there for your specific requirements and goals. Those can range from the walking distance between crops that need to be tended to regularly, to what the surface of the ground is composed of.

Concrete is a top choice as it can be laid level and smooth and, although expensive, is a good option if wheelbarrows are to be used frequently, as well as being easy to clean. Gravel, pavers, and even dirt can be used, each having its pros and cons, from price, ease of availability, to lack of drainage and uneven surfaces that can impede the movement of produce and equipment.

When the pros and cons of utilizing greenhouses in aquaponics farming are weighed up, the questions to be asked are not whether they should be used, but why are they not being used more often? The reasons for their usage easily fall into the positive categories.

Experienced farmers understand that aquaponics doesn’t need greenhouses to be a successful endeavor. But if greenhouse usage can increase productivity, can further protect the living organisms within, and in some quarters is being hailed as the future of agriculture, then surely, it’s better to be ahead of the curve rather than be left behind it.

Do You Need to Change Water in Aquaponics?

Aquaponics is very similar to Hydroponics in function and system design to a certain degree. Both are soilless systems and use water as the primary way of delivering nutrients. Hydroponics requires frequent water changes, so new gardeners can often ask the following question.

Do you need to change water in Aquaponics? Besides using fish as the source of nutrients in an Aquaponics system, the second most significant difference is you never need to change the water. You will need to top up water lost to evaporation, etc.; however, the system is self-cleaning when in operation.

Why Aquaponics Works?

Aquaponics is the perfect answer to a fish farmer’s need to dispose of nutrient-rich water, and a hydroponic grower’s nutrient-rich water demands.

Aquaponics mimics natural waterways and is a highly efficient way to grow food crops in small areas, yet systems are sustainable.

The primary input in Aquaponic systems is fish food, and as this is eaten, there is fish waste. Over 50% of the fish waste produced by fish comes as ammonia they secrete in urine and smaller quantities through their gills.

The remainder of this waste is excreted, where it goes through a process called mineralization. Here, heterotrophic bacteria consume the fish waste, decaying plant matter, and uneaten food, and all these create ammonia and other compounds.

Once the levels of ammonia rise above certain levels, they become toxic to fish and plants.

In soil, air, and water, you find Nitrifying bacteria, which can convert ammonia first into nitrites, and from there, they create nitrates that plants consume.

Heterotrophic and nitrifying bacteria cling to tank walls, under rafts, growing media, and organic matter in your system.

Such beneficial bacteria are natural and inhabit an aquaponic system when there is any sign of ammonia and nitrite present.

You have three things to keep alive and healthy in an Aquaponic system. You have your fish, plants, and the resulting beneficial bacteria.

All these rely on each other to live and create a circulating system where every party’s needs are fulfilled. Bacteria consume fish waste to keep the water clean for the fish. Meanwhile, the bacteria provide plants with a supply of usable nutrients.

As the plants grow, they use these nutrients, and by doing so, they act as a filter to clean water the fish live in.

Is There Any Reason to Change Water in Aquaponics?

One of the key reasons you may need to intervene and change the water in an Aquaponic system is if you have a severe algae problem.

Algae is a major nuisance and can cause many problems. Two areas that it can affect are the nutrients for your plants and your system’s pH.

An aquaponic system is a self-contained eco-system, and it is for this reason you shouldn’t have ever to change your water.

Not only this, but when you first build a system, they need to cycle to produce the right environment for your plants and fish.

Before you consider changing water, here are some things you can do to help prevent the accumulation of algae.

Shading

Shading is the quickest and easiest way to reduce algae in your system. Green algae need light to grow and reproduce. You can use either shade your tanks or cover them with a dark-colored tarp or plastic.

Many growers do paint sump tanks and any transparent plastic black and then white on top as this can reflect the sun and stop water heating up.

On media beds, if you have algae issues on the surface of your media bed or Bato buckets, you can shade by adding more rock or gravel to stop light from reaching the moist areas.

Filtration

Mechanical filtration can play a significant role in algae removal. Equipment can be expensive, although it’s easy to build. You can use filters, screens, and vortex or centrifugal settlement equipment to remove algae from your system.

A grow bed in your system will act as a large mechanical filter and straining algae from your water.

Alternatives

One alternative some gardeners resort to is using Humic Acid. In a deep tank, you can see the water darken from the addition of this. It is this that helps stop algae growth. You can add humic acid as it is beneficial for your plants to help chelate plant nutrients.

Why You Don’t Need to Change Aquaponic Water

Besides ensuring all your pipes and pumps are clean and working correctly. You will find little you need to do in dealing with your water besides checking pH levels.

You will discover much of this because an aquaponic system creates an eco-system rather than a system, which is fed nutrients as in Hydroponics.

Here you can see the functions of the three zones you will have in your system. It is the function of these to deliver nutrients by breaking down waste—the distribution of this nutrient-rich waste and the sealing layer that aids in preventing evaporation and algae growth.

One thing to note is the depth of your grow bed. It is recommended to have 12 inches, although many growers say you can use a regular hydroponic flood table. While possible, it makes the zones far thinner and restricts the range of vegetables you can grow.

Besides the volume of growing media (gravel) and your grow beds’ weight, it is advisable to aim for twelve inches for the best conditions.

Here is a breakdown of the zones and their function.

Zone 1 – The Surface Zone

The uppermost 2-inches of the surface serves two functions. First, we saw it stops a considerable amount of moisture evaporation because of the dry zone it creates.

Second, pea gravel that is dry in this area helps stop collar rot on your crops. You’ll also find the chances of powdery mildew are reduced, and as we have seen, it can stop algae growth.

Zone 2 – Root Zone

Of all the three zones, it is here where the most activity happens, and all the magic happens. You’ll find this root zone ends up around 6-8 inches in depth. Once the bed has been flooded and drains, you get optimal oxygen delivery to your crops’ roots.

All the activity comes from microbes, worms, and beneficial bacteria that accumulate.

It is the flood cycle that distributes all the waste particles across the growing bed. Works break down any solid matter and release minerals into the worm tea. When you flood again, this worm tea mixes with your water to spread around the roots of your crops.

Zone 3 – Mineralization

In the lowest 2 – 3 inches, you find a slurry of fish waste solids and worm castings. From the first entrance to the system, they will be reduced by around 60% in volume.

Once you carry out your flood and drain cycles, the zone receives a boost of freshness by the actions of the most recent delivery of oxygen-rich water.

Conclusion

You have no reason to change the water in an aquaponics system, yet this doesn’t mean you won’t have maintenance. Even with filters and everything else in place, you can end up with blocked pipes or water pumps.

Your system will do as much as it can to care for itself, yet to make sure you get the best results, it doesn’t hurt to add a helping hand.

Do You REALLY Need A Biofilter For Aquaponics?

Any beginner entering into the aquaponics sphere at one point or another will have this question or topic raised. Being newbies, they simply won’t know what to do at this early stage of their learning curve. But to be honest, there are many experienced growers who are also on the fence, hearing many conflicting voices for and against its usage.

The need for a biofilter is bacteria-driven. Beneficial bacteria are an integral component in the recycling system in aquaponics and help to harmonize the existence and wellbeing of the fish inhabitants and the burgeoning plant life. For a harmonious co-existence, a biofilter is a must have

Why Is A Biofilter Needed In Aquaponics?

Imitating nature is the underlying tenet of aquaponics, creating an environment of co-dependency between fish life and plant life. To flourish symbiotically, each relies on the other for nutrients, food, filtration, the conversion of waste materials into nitrates, and the ability to recirculate cleaned water back into the system.

This self-sustaining environment combines the benefits of aquaculture with the system of hydroponics, but it wouldn’t function quite so harmoniously and seamlessly without bacteria. To understand the need for bacteria it is necessary to know how aquaponics work, and that will determine whether a biofilter will be required or not.

The overriding principle with aquaponics is that there is no reliance on fertilizers to aid in plant growth. That chore is undertaken by nutrients. But where do they come from and how are they replenished?

A closed-circuit system like aquaponics utilizes the water from the fish tank to transport nutrients and water in a closed-circuit cycle. known as the nitrogen flow cycle, to the roots of the plants and back again.

The process is initiated by the waste of the fish and as this waste material begins to decay it starts to be broken down into ammonia. If left unchecked, this ammonia will turn toxic to the underwater dwellers and eventually lead to their demise. Adding to this build-up of ammonia will be the decaying organic matter of leftover food and dead plant segments.

In aquaponics, a conversion process starts to occur due to the interference of beneficial nitrifying bacteria, where the mounting toxic ammonia is converted into nitrite compounds. At this phase, the danger to the fish has been eliminated but the nitrite is still not usable for the nourishment purposes of the plants. What they need are nitrates.

A friendly bacterium called Nitrobacter is the leading protein in the oxidation process that will ultimately convert nitrites into nitrates, so the nutrients can now be absorbed as plant food. Without this beneficial bacterium, the aquaponics farm would fail.

So, if this system functions so seamlessly without any intervention required, why would a biofilter be needed?

The aquaponics closed-cycle system works when there are sufficient beneficial bacteria to complete the conversion cycle. If there is a shortfall due to a lack of surface area for the bacteria to grow, then more bacteria have to be introduced somewhere along the conversion line to make the world go around.

How A Biofilter Works In Aquaponics

Biofilters are essentially a large surface area attached to the aquaponic farm where additional bacteria can set up a colony and grow, increasing the efficiency of the nitrification process if it is underperforming.

Bacterial conversion, from ammonia to nitrites to nitrates, occurs in all aquaponics systems. The need for a biofilter can become necessary if there is an increase in the fish stock in the tank. This can be the result of a spike with breeding, and if so more fish generally equates to more poop, and proportionally more waste means more ammonia.

If this accumulation continues unchecked, the aquaponics farm can enter into the forbidden zone very quickly. Therefore, it is imperative to recognize when the biosphere is in jeopardy and act accordingly to expand the playing field. Fortunately, a biofilter will correct this imbalance automatically if connected to the circuit.

The setting-up process of interconnecting the two and expanding the surface area is not that complicated. It consists of another tank with one or more air pumps that are used to push water from the new side to the old, so they now operate on the same circuit.

Sand or gravel is most commonly used as the growing medium as it allows the colonization of the bacteria to progress easier. Nitrifying bacteria start to proliferate on the expanded surface area and, because bacteria require oxygen to grow and thrive, the biofilter should be set for additional aeration for maximum growth.

Plants will now be able to perform their duties after receiving the nutrients, by cleaning the water which is then returned back to the fish tank to start the cycle all over again. This expansion increases the efficiency of the nitrification process considerably.

All of this process is important to the chemical stability of an aquaponic biosphere, the wellbeing of your fish, and the successful growing of your crops. And the good thing is that nothing goes to waste, recycled as it is again and again.

A Biofilter in All Aquaponics Systems?

An aquaponics farm is in essence its own filtration system. And an efficient one at that. But with two living organisms to co-exist together a balance has to be reached or one will thrive and the other will decline. There are several factors that need to be considered.

The pH balance is front and center among them. A reading of 7.0 to 7.5 is considered neutral and is ideal for both organisms. If that level drops below 6.0 the nitrification process will slowly grind to a halt and become toxic to the fish and the plants will not receive enough nutrients.

Regular monitoring will detect the pH imbalance which can then be corrected before it gets into this danger zone.

This recalibration occurs naturally in a system that has a growing medium of gravel, clay or lava stones as long as the surface area is large enough to encourage bacteria growth. In this case, a biofilter will not be necessary, the grow beds themselves being the ultimate biofilter.

Problems occur, however, when this natural filtration system is overwhelmed by fish waste. This imbalance arises if more fish are added at a later date, or more fish are birthed in the tank, or even if too much fish food is being entered into the habitat, not eaten, sinks to the bottom and starts to decay. Either one of these will spike the production of ammonia.

Types of Biofilters

When installing a biofilter the location has to be situated after the mechanical filter as it is not designed to handle large fish waste deposits which can become trapped in the pipes. If this happens, the waste will continue to accumulate, creating an aerobic zone that will encourage excessive bacteria growth away from the expanded surface area which will not be utilized, and that will reduce the efficiency of the biofilter.

The mechanical filter acts as a screening filter to control this build-up of solids so the level of ammonia will not become too much for the biofilter to cope with.

There are various models of biofilters but these three are the most frequently used:

A Moving Bed Filter, also known as a Moving Bed Biological Reactor (MBBR), is a biofiltration model that is constantly in motion and at its core revolves around K1 media and constant aeration.

K1 media are made of small plastic discs and are ideal at trapping particles suspended in the water, and their large surface area encourages the growth of bacteria. With their virtual neutral buoyancy ability, they are subjected to a steady stream of air pressure that aerates the water and pushes them around.

This type of biofilter is essentially a constant flow system that uses an air pump to keep well-oxygenated water churning over, essentially creating a biological reactor. This system keeps the K1 media floating and in motion, assisting in the collection of good bacteria, and is especially effective in a raft aquaponics system.

Due to the collision of the media, each disk performs a continual self-cleaning process and this helps by keeping the nitrifying bacteria rejuvenated for optimum ammonia and nitrite nitrification.

A Static Filter biofilter has the advantage of the ease of use and ease of setup. It is essentially a flat tray in a separate container next to the plants, filled with a media mat to provide a sufficiently large enough zone to grow the necessary bacteria needed for the biofilter to work to its fullest potential.

The deeper the media incorporated, the more beneficial bacteria will be nurtured. Here, the principal theory is the water flows through the tray at one end into the media, the conversion from ammonia to nitrates occurs, and the cleaned water flows out through the opposite side back into the closed system.

With a Drip Filter, the water drips into the system from the top, passes through the bio medium at a slow rate, performing the vital conversion process from ammonia to nitrates, and flowing out the bottom on its way back to the fish, completing the cycle.

The Need For The Biofilter

A biofilter doesn’t have to be a part of the aquaponics system from the initial set-up. It can be integrated at a later stage as and when needed. The good news is that its inclusion isn’t a costly addition, and some would say it’s better to have it in place on standby if needed urgently. It is always better to have a quick fallback solution on hand if a nasty build-up of ammonia surges unexpectedly.

The fact that a biofilter requires very little maintenance is a reason all in itself to have one. There is no downside to having one even in this self-sufficient aquaponics biosphere. It can be implemented at any time to regulate ammonia, supplying enough oxygen for additional bacteria growth when required.

Sometimes adjustments in the aquaponics system can create an imbalance between ammonia build-up and lack of nitrates. This can occur due to plants being replaced, reduced and the opposite reactions can occur if the fish population is increased.

What has to be considered, and is often overlooked by beginners and some experienced aquaponics farmers, is the age of the fish being added into this bio-sphere. To maintain the equilibrium a specific stocking method has to be adopted.

This includes having a staggered age range of the fish throughout the same tank and employing a harvesting regime every three months. A recommended approach is to harvest the more mature fish who are now weighing about 500g and restocking them with new fingerlings or juvenile fish weighing about 50g each.

This staggered approach is to avoid swapping out of all the fish at the same time and to alleviate the sudden impact on the system. If a full fish exchange took place at the same time, out with the old and in with the young, then that would result in too much of a drastic adjustment requirement in regards to the filtration process.

Another reason for implementing this rotation is because larger fish tend to eat more than their juvenile co-inhabitants. And when larger fish if eat more they are going to excrete more waste. If this re-stocking process is not utilized, ammonia can reach unfavorable levels, rising completely unnoticed until something starts to die off.

Monitoring and reacting to this fluctuation can take years of experience as well as constantly keeping a close eye on the ph level. With a biofilter connected, these fluctuations are automatically adjusted as the water and the waste are washed through it, maintaining the delicate balance of this bio-diverse system.

The bottom line, the final word, on if a biofilter is necessary for a self-sustaining system like aquaponics, is yes.

Without one, time-consuming re-calibration tasks would need to be incorporated into a more frequent maintenance routine.

With one, your aquaponics farm will be a problem-free dream to run, and your plants, your fish, and your precious time will be the happy beneficiaries.

Can You Grow Onions in Aquaponics?

Onions are a staple diet for millions of people around the world and are grown in a myriad of environments to add flavor and texture to many a dish.

The idea of growing onions in an aquaponic system is not only possible but maybe a preferred method of farming to achieve a growing system that would reap a more organic harvest than traditional outdoor planting.

You can grow onions in aquaponic systems. Flood and drain or Nutrient film technique (NFT) systems tend to work best as the roots of onions need plenty of moisture.

Let’s have a look at how this system would work.

Onions and Aquaponics

Growing onions in a field is a labor-intensive farming method and requires pesticides, herbicides, and chemicals to eliminate pests and diseases. And they need a lot of watering.

There are several new revolutionary ways to grow crops over the last few years that have enabled city dwellers to grow onions, fruits, vegetables, and even grapes in an urban environment. These methods have breached centuries of traditional farming and have, in many cases, made it possible to grow staple food products in areas previously unviable and unachievable.

All these systems rely on regular maintenance techniques and nutritional systems to assist in the growing process, and any failure in the chain can lead to a lost or diminished harvest.

In aquaponics, the best of each of these techniques are utilized in a controlled environment to nurture the growth of onions, while the downsides of many of them are discarded.

No pesticides or chemicals are used, the time-consuming maintenance process is eliminated and even the harvesting process is simplified.

Aquaponics is about harnessing the power of nature itself to create a self-sustaining eco-system. It works by converting the natural waste of fish into nutrient-rich water that is transported through the system to be absorbed by the roots of the onions, and then the cleaned water is returned to the fish tank.

Once the system is installed there is very little ongoing work or maintenance required. This closed-loop aquaculture works harmoniously with the onions and the fish flourish mightily within this self-contained eco-system.

How to Grow Onions in Aquaponics

Creating a continuous cycle is the tenet of aquaponics.

This particular method requires an aquarium, a pump to move the water back and forth from the aquarium to the roots of the onions, a grow bed where your onions will be located, and a selection of fish for the tank itself.

The grow bed can either be placed on top of the aquarium or off to the side. The grow bed, or flood table as it is also called can simply be a plastic tray or a large container as long as the support structure is strong enough.

Once you have decided on the location and how big you want your aquaponic farm to be, select the size of the aquarium. By using an aquarium instead of a solid container, gives you the benefits of having and enjoying your pet fish while growing your new onion crops at the same time.

At this stage prepare the fish tank as normal by dechlorinating the water and then allowing sufficient time for the bacteria to build up over the following weeks.

This is the starting point to set up your very own fully integrated ecosystem. It works by having the natural waste from your fish being broken down into nitrates, and then a pump carrying these nitrates to feed the roots of the onions. Nitrogen is then released by the plants, cleaning the water which is then safe to be pumped back to the fish, and then the cycle is repeated.

This process is on a continuous loop and the only time water has to be added is if there is a marked level of evaporation or if it is transpired by the plants.

Three Ways to Grow Onions in Aquaponics

There are essentially three types of aquaponics that are used depending on growing experience, the space available, and the scale desired.

The Deep-Water Culture Set Up lets the onion roots drop into the water and take nutrients directly from the water. This method is suitable for a larger scale operation.

The Nutrient Film Set Up is where the roots are left to dangle in a PVC pipe drilled with holes. The water is drawn into the pipe to run over the roots, delivering much-needed nutrients before being fed back into the tank. This method is suitable where space is a consideration and is flexible enough to allow crops to be grown vertically, horizontally, up walls, or even hung from ceilings.

The Media Bed Set Up is the last method and is the most convenient for home growers with little experience, and who opt for a smaller-scale operation. Here the plants are seated in a bed of expanded clay pebbles or gravel, and a pump draws the water from the tank to flow over the roots.

Normally onions require space between the next clove to grow as about a dozen shoots sprout above ground. In aquaponics the bulbs can be set a mere inch apart, allowing more to be grown in a smaller area.

Caring for your Onions in Aquaponics

Growing onions with aquaponics will give you the option to decide how big you want to grow, whether your intention is to feed a small household or a community of onion lovers.

It all depends on the size of the area you have available, from a ledge in your bedroom to a large greenhouse in a nearby field, and, of course, what your goals are. Even the strain of harvesting can be mitigated with the grow bed set to a height totally at your discretion for comfort.

Less water is used due to the closed-loop ecosystem, with hardly any at all being wasted. With this consistent water availability, the bulbs have a tendency to start sprouting quickly as long as the temperature range of between 55°F to 75°F is maintained.

Aside from the importance of having the correct temperatures, having the ph level right is just as crucial, but it can be a little tricky. The onions, the fish and even the bacteria being formed in the water are three distinctly separate living organisms, and all have different ph requirements.

This ph level can be affected by the fish waste, and that can adversely impact the ability of the plants to absorb nutrients, which will reflect negatively on the lives of the fish. So, as you can see the balance of the eco-system as a whole has to be finely tuned regularly.

The optimal range of ph for aquaponics is around 7.0. To ensure a continued harmonious system, it is advisable to monitor this neutral ph balance on a daily basis to avert any wild fluctuations and to keep within this ph safe zone.

And the type of fish selected for this project can make the task of maintaining your onion farm easier also.

One of the ideal types of freshwater fish to use is, believe it or not, is the humble goldfish. They tend to excrete large amounts of waste so your onions won’t be short of nutrients in the conversion process.

But koi can be used, as well as tilapias, and really any hardy fish will do that require minimum maintenance. After all, the beauty of aquaponics is not just the onions you will be growing tenderly, but the aquarium full of colorful, interesting fish that you will be enjoying at the same time.

Harvesting Aquaponic Onions

Aquaponics is a symbiotic relationship between plants and fish and goes hand in hand with sustainability. This collaboration uses less water which is cost-effective and good for the environment and produces 100% organic produce.

Really there is no limit to where your onion crops can be grown with aquaponics and an added bonus is that the growing times are accelerated. This results in a quicker crop of onions being harvested more frequently and, due to this system being so self-contained and self-reliant, the whole interconnected process becomes a game-changer in the field of growing onions.

All in all, aquaponics combines all the new innovative growing methods together with the flexibility to be scaled to fit over a small aquarium filled with an array of multi-colored fish, or scaled upwards for a much larger industrialized farming operation.

Can there be a better way to grow your onions?

Can You Grow Broccoli in Aquaponics?

When you first run either a hydroponics system or an aquaponics system, it’s hard to know which crops are best to grow.

The smaller systems lean toward shallow rooting vegetables, which are mainly herbs or leafy green sorts of vegetables for salads. However, larger systems can cater to larger crops, and with space, they are perfect for tomatoes, cucumbers, peppers, or other vining vegetables that need room to spread.

The question comes down to root vegetables and the possibility of growing them. You can find out the answer, and then other information about growing this healthy vegetable.

Can you grow Broccoli in Aquaponics? You can grow broccoli in your flood and drain media bed or Dutch bucket type system. You find broccoli isn’t so much a large crop; it is heavy. This weight makes it unsuitable for floating rafts, nutrient film, or other similar systems. It is worth growing in larger, supportive beds. However, there are a few other growing demands of this healthy crop you need to know.

Broccoli and Nutrient Requirements

To grow broccoli efficiently, they require lots of nutrients, and thus you may need to adjust the fish population to accommodate this crop.

You will also find it far better to attempt growing broccoli in aquaponic systems, which are well established. Fish levels may be better if they are around 1lb of fish per eight gallons of water rather than 1lb of fish for every 10 gallons.

With a perfectly functioning system, the nitrates’ levels should be 50ppm or as close to this as possible. Besides this, the levels of ammonia need to be low, even with increased fish density.

Besides this, the other two key nutrients are magnesium and phosphorus, or you may see crop growth slow.

Growing Instructions

When you come to transplant seedlings into your media bed, you ought to do this once they have 4-5 true leaves showing. Your crops at this stage will be around 5.5 to 8 inches tall.

The germination time to reach this stage can be around 4 to 6 days. Besides this, you need to consider the spacing for transplanting as broccoli comes with a large root system.

Seedlings should be planted from 17 to 20 inches apart from each other. Closer than this, and you can see your crops producing smaller central heads.

Growing Conditions for Aquaponic Broccoli

Broccoli is a winter vegetable and won’t take too kindly to growing conditions that are too warm. While it is a beneficial crop to grow, it is on the side of moderately difficult.

You can find seeds that will be bolt resistant to help, though trying to maintain the ideal temperatures will help considerably. Broccoli thrives the best in daytime temperatures of 57 – 62 F (14-17 °C).

Winter varieties will require temperatures around 50 – 59 F (10-15 °C) for the head formation. Temperatures above these are possible, so long as there is a higher humidity level available. Should temperatures be too high (over 65°F), this will cause premature bolting.

Also, broccoli likes full sun for around 6 hours per day. It can cope with a little partial shade, although this could make broccoli mature at a slower rate.

Broccoli can deal with swings in pH levels, although for the health of the rest of your system, aim to keep it at a more neutral level of pH 6 to 7. A digital pH pen is ideal for checking the levels frequently.

Harvesting Broccoli

It would be best if you started harvesting broccoli for the best quality when head’s buds are firm and taut. Harvest immediately when the buds separate and show their small yellow flowers. To preserve taste, it is important to harvest the broccoli in the morning.

You should cut the heads off your plants and take at least 6 inches of stems diagonally below the head.

Most varieties of broccoli have side shoots that develop after the chief heads are harvested. You can harvest from one plant for several weeks, sometimes, from winter to the beginning of summer as long as summer temperatures are not too hot.

Pests and Disease in Broccoli

Many crops in your aquaponics and hydroponics systems often face less intrusion of pests and disease. Although broccoli is one that, like cabbage, can be prone to the effects of cabbage worms and other pests.

Here are some pests or disease you will need to be wary of when growing broccoli in aquaponics.

  • Aphids: Curled leaves may show the sap from your broccoli is sucked up by insects. A way to combat this is to apply soapy water on all sides of your leaves whenever you see aphids.
  • Cabbage Loopers: If you see small holes in your leaves between the veins, they may result from green caterpillars. Check the underside of the leaves. You can pick these off by hand if the problem is small or fight the problem with Bacillus thuringiensis, a natural bacterial pesticide.
  • Cabbage Worms: Such worms, Whiteflies, or cabbage root maggots can be treated the same way as you treat any cabbage loopers.
  • Clubroot: Rapid wilting of plants can be attributed to this fungus. Your entire plant, including all its roots and tendrils, needs to be carefully unearthed and removed from your media bed. If roots appear gnarled and misshapen, then the root of the club is causing the problem. You will need to remove infected plants swiftly, so the fungus will not continue to spread throughout your system.
  • Downy Mildew: When purchasing broccoli seeds, make sure you purchase varieties resistant to downy mildew. Otherwise, you will spot the yellow patches that are caused by moist conditions. Aim to keep crops dry, and they have plenty of air circulation.
  • Nitrogen Deficiency: Broccoli is a nutrient-loving vegetable. If your fish tank isn’t large enough to cope with numerous broccoli plants, it could lead to a slight yellowing of the bottom leaves rising upward on your plants.

If you have the capacity, you can plant marigolds or calendula flowers close to your broccoli as these help fend off the above pests that take a liking to your crops.

Aquaponic Broccoli Varieties

While there are many varieties of broccoli available, not all are suited to aquaponic cultivation. Here, we have the top three to consider should you decide on broccoli for your soilless system.

Chinese Broccoli

Despite being a broccoli variety, it differs greatly from other cultivars because it grows without florets. Also known as Kai-Lan or Chinese kale, this variety has large, thick leaves with a bitter taste compared to Calabrese and sprouting broccoli.

Chinese broccoli grows quickly, at around 35 days, and thrives well in warmer environments, making it ideal for growing in the summer.

Sprouting Broccoli

In contrast to Calabrese, this kind of broccoli shows more stems and smaller single florets than a central head. Sprouting broccoli is more bitter than other species and can be purple or white.

White-sprouting broccoli is milder and slightly sweeter in flavor than its purplish equivalent.

Calabrese Broccoli

You will be more familiar with the Calabrese Broccoli since it is the most commonly sold variety in stores and markets. The heirloom plant was named after Calabria or “the toe” from the Italian peninsula.

Gardeners highly recommend it because Calabrese broccoli offers an extended harvest period, as it forms side shoots that remain in place after removal of the main head.

Conclusion

Although broccoli can be more challenging to grow than many other crops, so long as you have deep grow beds to offer support and maintain the desired temperatures, there is no reason you can’t dedicate a grow bed to this crop.

While it is usually a large grow bed, you can use a Dutch bucket system to make sure they have ample support. You then have the flexibility of your spacing and won’t waste valuable space in your main bed.

While a challenging crop, broccoli is worth the effort because of its rising costs in the stores and its many health benefits.

What Size Gravel is Best for Aquaponics?

In the same way that hydroponics is a soilless means of growing, so is aquaponics. One of the key differences being the way the grow beds are constructed. While hydroponics systems tend to grow in pots in various systems, an aquaponic system most often uses flood and drain grow beds, which are full of growing media. Gravel being the most common.

What size gravel is best for aquaponics? There are many sizes available, and in theory, any size gravel can be used. Most hydroponic gardeners prefer pea gravel, which is between 1/8 of an inch up to 3/8 of an inch in size. Although, the smaller 1/8 sized pea gravel being the gravel size of choice. 

Considerations of Aquaponic Growing Media

When you first build any aquaponics system, there needs to be a few considerations when choosing the ideal growing media. Here you can find the things you need to think about, and you can see why pea gravel is the ideal media to use.

Inert: Any aquaponic grow media needs to be pH neutral. Similarly, as a hydroponic system, the pH level in an aquaponic system needs to be controlled.

Fish and plants have their preferred range of pH range, and ideally, you need to aim for a range of pH 7. Many media can change the pH level, although pea gravel isn’t one of them.

All you need to do is thoroughly cycle your system before adding fish or plants to clean away any dust.

Grow Bed Depth: Any grow bed in aquaponics should be a minimum of 12-inches deep for most crops.

Weight: Any grow media in use in a hydroponic system should be too heavy to handle. It should be light to medium weight, so you can easily dig your holes when you plant your seedlings. On the flip side, if they are too light, they can float in the grow bed and won’t offer support.

Easy to Work With: Grow media can comprise any size or shape, although sharp edges are best avoided. If you use sharp-edged stones, these can be hard on the hands and damage any grow beds that are not constructed from solid materials.

Non-Decomposing: No aquaponic grow media should break down because it can work its way through your system and clog your water pump and reduce dissolved oxygen in the water for your fish.

Pea Gravel for Aquaponics

Pea gravel fits all the criteria and then some. The smaller pea gravel has a large surface area that bacteria can thrive on. With this, the nitrogen cycle is complete and, in turn, delivers robust plant growth.

From the fish waste, the broken-down compounds create ammonia, which passes around your system. Once it flows through your smaller sized pea gravel, it is converted into nitrites by two bacteria strains (Nitrosomonas bacteria).

From here, these nitrites are consumed by the second strain of bacteria (Nitrobacter bacteria) and converted to nitrates. Your crops then use the nitrates as fertilizer.

As there is more surface area on the gravel, a larger number of nitrates are being produced than if larger gravel was being used.

Pea Gravel with Limestone

Generally, your pea gravel won’t contain anything to change your aquaponic system’s pH level radically. However, if there are any traces of limestone, the results could be different.

Before filling your grow beds, you can carry out a test to check whether your bags of small pea gravel.

Take a handful of gravel, place it in a container, and then cover it with some white vinegar. You can see the vinegar fizzles if there are traces of limestone.

You need to avoid limestone as this will keep your pH above 8, which can harm your plants and your fish.

You can place some gravel in distilled water and check the pH after a couple of days, although it is better not to purchase any gravel you think may be suspect.

One thing to note is that the name pea gravel isn’t a type of gravel, it is because of its size. One dealer can sell something different to another.

Grow Bed Depth and Pea Gravel

One thing any gardener needs to understand when using pea gravel is the depth of the grow bed. The recommended depth is 12 inches, and for a good reason. When building a system, you may be tempted to go for a shallower bed.

Even while pea gravel is the cheapest media you can purchase, the amount you need could be considerable. However, there are reasons why you should opt for a grow bed of this depth, if possible.

Here you can see why avoiding the shallower bed sizes can be beneficial, and it is advisable to scale your system to support the larger bed and the increase in the size of the fish tank you will require.

You will face limitations if you decide to go for a shallow grow bed filled with pea gravel.

Eco-System & Dead Zones

In deep aquaponics grow beds, you naturally create a layered eco-system. One significant benefit of this is that you will prevent any ‘dead zones’ dotted around your grow beds.

Besides this, as you have a thriving environment packed full of beneficial bacteria, worms, and lots of space for roots to grow. You don’t have to clean out your grow bed.

These bacteria and worm communities, along with your plants, do all the cleaning for you. Anything less than 12 inches, and you won’t be able to reap these benefits of a stable eco-system.

Plant Limitations

If you are growing nothing but crops similar to lettuce, you may get away with a grow bed shallower than 12-inches.

However, if you grow indeterminate tomatoes, cucumbers, and corn among the many other crops that can benefit from aquaponics, these shallow beds can’t support them. You won’t receive the same base nutrients and beneficial bacteria for these longer living crops.

One thing not to forget is your aquaponic system can be highly configurable, and you can mix grow beds and use raft systems for short rooting crops and larger grow beds or Dutch becket systems for deep-rooted crops.

Three Zones of Pea Gravel Grow Bed

Zone 1 – Surface Zone

The top 2-inches serve two purposes. It allows for light penetration and acts as the dry zone to limit evaporation. The second reason for this dry zone in your pea gravel is to prevent collar rot and stop any algae forming as the nutrient-rich solution faces light exposure. Also, the infection from powdery mildew is minimized.

Zone 2 – Root Zone

It is in the second or middle layer where the plant activity occurs. Making up this layer is around 6 to 8 inches in depth. As you drain after flooding your grow bed, water drains away completely and presents highly efficient oxygen delivery to the roots, microbes in the soil, worms, and beneficial bacteria.

When you are in the flood cycle, incoming water will distribute all the fish waste particles containing nutrients through the entire grow zone. Worms are highly active in this middle zone, where they break down solid matter to release minerals and add to the underlying worm tea. On each successive flood and drain, this beneficial tea is spread around all your crops.

Zone 3 – Solids & Mineralization

Once you reach the bottom 2-inches, you find all the fish waste solids and worm castings are gathered together. By the time it reaches here, it will have been reduced by around 60%.

In each of your flood and drain cycles, this zone is kept fresh from the effective delivery of oxygen-rich water.

Conclusion

Once you see the benefits of using 1/8-inch pea gravel, you can understand why it is among the most popular media.

It is highly affordable, and any gardener is advised to lean toward the deeper grow beds when possible. Besides this, there is nothing you need to do with pea gravel, and it is one of the easiest materials you can work with.

There is nothing but benefits you can get from using this smaller sized pea gravel than if you used a larger gravel, or an alternative growing media.