Some say it’s important to dream big… and it is! But what if that dream was already made possible? What if producing healthy plants and fish was possible in a space as small as your closet? Aquaponics, similar to hydroponics, have plants growing in a medium without soil, where roots are constantly hydrated. Given that aquaponics can produce a variety of plants, it has quickly become popular in developing regions of the world. Aquaponics offers one of the most self-sufficient household farming concepts currently available.
Aquaponics offer the same benefits as hydroponics of water conservation and optimization, while also producing fish for our consumption. Aquaponics consume 90% less water per plant than in conventional agriculture. The current environmental affairs of the world include intense and frequent droughts where crops are drying out in fields and leaving farmers out of business, historic lakes and rivers are drying out, and international conflicts over water usage. With the amount of effort needed to feed some goldfish, you can deliver nutrient-rich water directly to plants, removing the possibility of excess irrigation, and minimizing evaporation rates.
For this reason, aquaponic systems of all types and sizes can be found around the world where they are needed most. The reason for this is that working people in developing nations do not have the time to fine tune hydroponic systems; an aquaponic system only requires feeding and monitoring once a day for a protein-rich yield. Imagine producing an entire fish and salad meal from the convenience of your closet or balcony.
We would strongly recommend you read our “How To: Hydroponics” as it serves as the foundation for Aquaponics and covers elements that are not covered here.
How does it work?
- Household Ecosystem
Aquaponic systems closely resemble a functioning ecosystem where plants and fish need each other at equilibrium for a fruitful survival. In a hydroponic system you would have to pour in nutrient solutions to keep plants alive and thriving whereas in aquaponics it is as simple as feeding a goldfish.If the plants in the system use up all the nutrients produced by the fish, leave the water clear, and appear to be healthy, then the system is at equilibrium.If the water is clear, yet plants are struggling, then there is a shortage of waste being produced by fish. Inversely, if plants look healthy and the water is murky, then the fish are producing too much waste and can be lethal.The most specific ecosystem resemblance of aquaponics is that of the Nitrogen Cycle. Fish in the reservoir eat a selection of food which then causes them to excrete ammonia rich waste. Ammonia, even in small concentrations, is very lethal to fish and will only continue to increase if nothing is in place to remove it. Fortunately, ammonia becomes food for plants which then brings equilibrium to the system.
- The Nitrogen Cycle
But is it as simple as feeding ammonia to plants? Not really. Ammonia is an unusable form of nitrogen to plants. When ammonia-rich waste is produced by fish, a kind of beneficial bacteria known as Nitrosomonas converts it to nitrite which is then converted by another beneficial bacteria, Nitrobacter, into nitrate. The nitrate, the least toxic nitrogen form to fish, is then consumed by plants as a powerful fertilizer.We would recommend you take a look at our Hydroponics Guide for a more thorough explanation on the mechanics of pumps, water, aerators, and plants.
Aquaponic gardening does not need to be very complicated. A number of systems have been developed which follow the same basic principles and contain adjustments dependent on scale, plant needs, and desired outcome. In order to narrow down your search we have compiled a description of the three most successful systems which, in our experience, get the job done. Aside from practicality, we also cross-checked our list to be as cost-effective as possible.
- Continuous Flow System
The image you most likely have in your head of a system where water is continuously circulating is known as a Continuous Flow System. This system keeps water circulating to roots constantly which allows for an even distribution of nutrients to water-loving plants.Although some of these systems maintain roots completely submerged, the Nutrient Film System is one where root tips are constantly in contact with water without being totally submerged, which saves energy and increases aeration.
- Intermittent Flow
In the quest to both conserve energy and allow plants to keep their roots submerged for most of the time, a system known as Intermittent flow was created. This system is ideal if you do not have your system hooked up to solar, want to conserve energy, and would like to grow plants that rather remain submerged, such as lettuces.The intermittent flow system works on a timer which activates the pump to fill up the grow beds with water from the fish tank every hour. The grow tank then empties itself via permanent drain holes at the bottom which send the water back to the fish tank. This sort of system eliminates the need for a continuous filling pump and continuous draining pump.
- Flood and Drain System
Also commonly used in hydroponics, The Flood and Drain system is known to be a simple system. Aside from the basics, it contains a submersible pump with a timer. The grow tray is flooded with water from the fish tank two to four times a day at approximately 30 minutes each: this equates to 15 minutes of flooding and 15 minutes of draining per cycle.The convenience of this is that water and nutrients can be fine-tuned to achieve optimal plant health and yields. We would remind you that this system needs to be monitored often as a failure to flood on time could leave plants without water for longer than they can survive. Once plants reach the wilting point, there is no turning back.
Living Components of Aquaponics
Fish are what set aquaponic farming apart from hydroponics. Although it might seem that hooking up your plants to a goldfish bowl will do the trick, you will also need to take into account the health of the fish in order to yield a healthy meal to eat.Common fish used in aquaponics are tilapia, carp, and catfish. Each fish should be thoroughly researched for specific feeding and breeding habits which will determine differences in management. Tilapia are typically recommended as the best fish for beginners looking to learn through experience, and of course as a versatile fish consumed in most cultural dishes. In reality, tilapia farming was being done 4,000 years ago by the Egyptians.Conveniently, Tilapia are hardy fish that can withstand failures in the situation of low aeration, higher ammonia, diseases and parasites, changes in temperature, and most other stressors. Given their hardiness, Tilapia can also eat just about anything. Their diet can even be supplemented with kitchen scraps like rice and bread. It is recommended that tilapia be fed 1 pound of tilapia per 10 adult fish up to 4 times a day.Tilapia can also be fed by algae growing in the tank which contains an array of nutrients needed for their healthy development. Tanks left in the sunlight will quickly develop algae which can feed tilapia.
Plants are complex organisms that have as vast a range of attributes as they have needs. As any complex organism, plants have cells that are specialized in certain functions, such as: structural support, transport of nutrients, making roots, converting light into food, and even breathing!Interesting groups of these cells together usually present themselves as noticeable parts of the plant, such as: roots, stems, and flowers.For a thorough profile on plants and their nutrient needs, please see our “How To: Hydroponics”
- Beneficial Bacteria
Beneficial bacteria are also a necessary component to this system but are found naturally in the air and water. They are needed to convert the fish waste ammonia into a form of nitrogen that can be used by the plant. Make sure to not use tap water as it contains chlorine which will inhibit algal growth. Ideally, use rainwater or well water for the aquaponic garden with a booster cup of water from a nearby healthy body of water to introduce an ample amount of beneficial bacteria.
Before setting up an aquaponic system in the convenience of your home, there are some considerations that need to be taken into account in order to minimize any possible hurdles.
- Fish out of Water?
For starters, float valves should be used in both the fish tank and grow tray to ensure that neither overflows or is left without water. Imagine the plant tray being full of water for 30 minutes in a Flood and Drain system where fish would be left dry for that same amount of time! This mistake is common for those who have experience in building hydroponics which do allow for reservoirs to go dry. In essence, ensure that the entire system has more water as a whole than is needed in the plant tray.
- Structural Support
Make sure your structure is strong and reinforced! Each gallon of water equates to 8 pounds plus however many pounds of fish you have. It is recommended that the heavier parts of the system be kept lower to the ground.
- To Algae or not to Algae?
Although sun promotes algal growth which tilapia eat, algae can also cause clogs in the filters and tubes which could cause sudden changes for the fish and plants. The smaller the fish tank, the bigger impact the sun has on water temperature; the inverse is just as true. Such drastic temperature changes could be lethal to fish. The safest bet is to keep your fish tank shaded from sunlight.
- Test Your System!
Once you have set up your system, run it for a few days before bringing in new fish. It would be a shame to lose your first group of fish to an easily avoidable technical error. This would also be an ideal time to practice using pH, ammonia, nitrite, and nitrate level tests which should become a habit for your system in order to achieve equilibrium.
Common First Problems
Here we will outline some common issues that occur in aquaponics. We will cover what they could mean and what to do:
- Fish Gulping
Are your fish spending most of their time on the surface gasping for air? This most likely means that there is not enough oxygen in the water. This can be remediated by ensuring your air pump is functional or by making the grow tray outflow water cascade into the fish tank upon escape to promote further aeration.
- Algal Blooms
If water starts to turn red or green with visible algae then you might have an algal bloom. This happens as a result of excess nutrients in the water. You could feed your fish less in order to ensure that no food is going to feed algae. Algal growth on the walls could be a sign of too much sunlight and could be fixed by shading the fish tank.
- Weak Plants?
Are your plants looking yellow or weak? If plants are looking deficient of nutrients, it is recommended to use an organic fertilizer such as seaweed extract. Do not use any synthetic fertilizers as they could be very lethal to your fish!
- Nasty Pests
A sign of slugs or snails in the system could be common as they seem to be attracted to places that are constantly wet. If you cannot pick them off and feed them to the fish then it is recommended that you flood and drain the grow tray; this should flush them straight into the mouths of hungry fish.
- Dead fish
Finding a dead fish in your system could be a sign of a variety of problems. This is usually due to an excess of ammonia which could mean that there are not enough plants and bacteria breaking down the nitrogen in the system. Fish kills could also happen if the water is not properly aerated due to a broken air pump. The most important thing is to remove and dispose of the dead fish immediately.
Let’s Get Started!
Now that you know all the basics to aquaponic growing, you are ready to get started! We would recommend getting started with lettuces since they are plants that grow easily without many adjustments and can be replaced easily if you make any mistakes at first. Experience will be your best teacher. Do not expect your system to be perfect at first, but it very soon will be!