Aquaponics is an agricultural practice that involves the combination of aquaculture, which is the cultivation of aquatic animals like fish, and hydroponics which is the method of cultivating plants without soil. This system operates through the establishment of a symbiotic relationship between the two by channeling the aquatic animal’s discharge or waste to feed the plants. In return, the plants help in the water purification process which eventually goes back to the fish. Furthermore, microbes act as a vital component in the nutrient cycle of the system, which proliferates in the spaces between the roots of plants and converts waste and solids from the fish into viable nutrients for plants. As a result, this system provides an excellent way to merge aquaculture with gardening.
Aquaponics presents a promising solution for achieving sustainable organic crop cultivation, aquaculture, and water usage. Through this method, fish waste is repurposed for plant nourishment instead of being disposed of in the ocean. Additionally, the water is constantly circulated within a closed system, minimizing the utilization of this valuable resource.
Types of systems
Aquaponics shares the same systems as hydroponics, resulting in minimal differences in operation, with the exception of including fish in the water tank(s). The irrigation methods of drip, flood and drain, deep culture or water-submerged roots, and nutrient film technique are easily adaptable and can integrate with fish farming.
Importance of pH control in aquaponics
Aquaculture relies on pH control, which can be challenging due to the varying pH needs of plants, fish, and water bacteria. A neutral pH ranging from 6.8 to 7.2 is suitable for aquaponics but maintaining this balance can be affected by fish waste. Adjustments using pH regulators specific to aquaponics are necessary if the system becomes too acidic or too alkaline, to avoid disrupting nutrient absorption by plants and prevent fish death. Consistent monitoring of pH levels is crucial for sustaining the system’s neutral range.
Maintaining the proper pH level is crucial for the survival of fish and plants in aquaponic gardening. Too much acidity or alkalinity can result in gardening failure. Hence, pH adjusters must be specially designed for this type of growing system to avoid endangering the fish. You could procure these adjusters from a local aquaponic gardening supplier. It is also important to consider water hardness because it affects pH adjustment. At times, one has to address water hardness while adjusting pH. Sudden changes in pH may be stressful for fish; hence, gradual changes are preferred.
Fish and other aquatic animals you can grow in aquaponics
Your plants are nourished by the fish. Tilapia and barramundi are the preferred species in this form of aquaculture as they can thrive in varied water conditions and grow rapidly. Trout is a viable option for colder water temperatures. Other potential aquatic beings for cultivation are shrimp and snails.
Special food for fish is available for purchase at animal stores, or alternatively, you may feed them water lettuce or duckweed.
What vegetables you can grow in aquaponics
Small aquaponic gardens are suitable for cultivating low-nutrient vegetables such as lettuce, kale, watercress, arugula, and herbs, as well as decorative flowers, okras, spring onions, leeks, radishes, and spinach. However, high-nutrient crops like cabbage, tomatoes, cucumbers, beans, broccoli, and cauliflower require a well-stocked and advanced aquaponic setup. It is advisable to steer clear of plants that thrive in acidic or alkaline water as these pH levels can endanger the fish.
Benefits of aquaponics
Aquaponics enables the simultaneous production of fish and vegetables by utilizing the waste output of the former as the feed for the latter. You provide the fish with food, and they in turn nourish your plants.
Fertilizers are unnecessary as the plants receive ample nutrients from the fish.
Aquaponics utilizes a reduced amount of water when compared to conventional crop cultivation. Studies indicate that an aquaponic garden consumes only one-tenth of the water needed for a soil garden.
The fish would suffer if conventional pesticides or other chemicals were employed for gardening purposes.
Healthier and organic vegetables are a consequence of this.
Aquaponics eliminates the risk of soil-borne diseases since there is no presence of soil.
It is possible to cultivate plants within limited areas and still obtain a bounteous yield.
Fish waste provides highly nutritious substances, causing plants to grow rapidly.
It is possible to cultivate plants and breed fish in an environment with regulated temperature.
By using a closed system and promoting effective circulation, water consumption and subsequent bills can be reduced.
What is aquaponics cycling?
The process of Aquaponics cycling involves the conversion of ammonia in the system into nitrites and subsequently into nitrates, which are essential nutrients for plant growth.
Fish produce ammonia as their waste product. If their water is not filtered, leaving them in it will result in their death, rendering them useless for the growth of plants.
By cycling, you prepare your system for the effective introduction of bacteria that convert ammonia and ammonium into nitrites and then nitrates.
If fish and plants are introduced to the system simultaneously, there will not be any bacteria available to transform the waste produced by the fish into nutrients for the plants.
Cycling refers to setting up an aquaponics system with the goal of establishing the necessary bacteria for the successful coexistence of fish and plants.
Why aquaponics cycling is necessary
Bacteria that convert fish waste to nitrates thrive and reproduce in cycling.
Making sure all the required components for flourishing plant growth are available is imperative during the initial phase of setting up your system through the process of aquaponics cycling.
Cycling options
There are actually two choices for aquaponics cycling: cycling with fish or cycling without fish. Both alternatives can be effective, and it’s just a matter of personal preference which one to select.
To cycle aquaponics, it is recommended to keep the water temperature between 68°F-86°F (20°C-30°C). The process usually takes about 4-6 weeks. If the temperature goes out of this range, the multiplication of bacteria required to convert ammonia to nitrates will slow down, leading to a longer cycling process.
Nitrosomonas and Nitrobacter bacteria reproduce best within a pH range of 7 to 8. If the pH of the water falls outside of this range, it will result in delayed bacterial development. One should avoid using lime to raise the pH as it can be fatal to the bacteria.
Cycling with fish
Prior to anything else, you must assemble your own system that involves a container for your fishes, linking your grow bed, the growing matter, and a motor, and the appropriate temperature and pH for the specific fish type you have selected.
Once you have ensured that the conditions of the water are suitable, you may introduce fish to it. It is advised to start with a small number of fish to prevent significant casualties in case of any mishaps. Hardy fish like goldfish are the ideal choice in this situation.
At this point, it is optional to include a bacteria starter, which essentially introduces the necessary bacteria to your system, promoting their growth and settlement. Failure to use a bacteria starter will still result in the accumulation and reproduction of bacteria, albeit slightly delayed.
To start the bacterial growth, you may use filter material from a pre-existing pond. It is important to ensure the absence of parasites in the pond.
After you have put in the fish, it is necessary to check the water daily. It is essential to maintain the ammonia levels below 2.0 ppm as well as nitrites below 1.0 ppm. The fish might experience stress and eventually die if the ammonia levels become elevated or if the nitrites levels fall too low.
If the ammonia levels exceed the permissible limit for your fish, refrain from feeding them until the levels drop. Some individuals claim that aquaponics poses a risk of E. coli infection. Despite this, the risk is quite minimal.
Fishless cycling
Without a doubt, aquaponic cycling can cause stress for both you and the fish. This is why an alternative method exists, which involves cycling without fish.
Once more, it is necessary to ensure that your system is set up and prepared for both fish and plants.
On this occasion, you include a bacteria starter to initiate the bacterial growth. To achieve a 4.0 ppm level, it is necessary to supplement with ammonia. Powder or liquid ammonia can both be utilized for the cycling process of your aquaponics system.
To maintain the ammonia levels around 4.0 ppm, it is necessary to carry out daily tests. It is recommended to test before adding ammonia and maintaining an interval of 24 hours between consecutive tests. When the ammonia levels drop to 0.5 ppm and nitrites appear in the water, the cycling process begins, and the addition of ammonia can be stopped.
Numerous techniques exist to introduce ammonia into your system.
Ammonia in a liquid state.
To ensure the well-being of plants and fish, it is crucial to utilize pure liquid ammonia that contains only 5-10% ammonia and water. Other chemical additives may prove harmful and should be avoided.
Although it is becoming more and more scarce, this could be the most economical choice.
Crystallized ammonia is also known as ammonium chloride.
It is essentially equivalent to liquid ammonia, but more readily accessible. It can be obtained from nearly any pet store or even a store that sells photography equipment.
It is noteworthy that this product is available in its dry form and is extremely concentrated, yet inexpensive to transport.
“Urine” cannot be rephrased with the same meaning as it is a specific medical term referring to the bodily liquid waste excreted through the urinary tract.
Animal urine, including human urine, contains high levels of ammonia. However, the advantage of using human urine is that it is easier to collect.
It is important to remember that if you are using human urine for your system, it needs to be stored in a sealed bottle for approximately 3 weeks. This time will allow the urine to undergo a conversion process and transform into ammonia. If you add it to your system before this process is complete, it can be difficult to keep track of how much ammonia is being introduced and levels may rise rapidly. Ammonia is recognized by its potent odor, which is often associated with urination.
Fish that are no longer alive.
Acquiring dead fish is not the best method because it not only raises ammonia levels, but it also introduces bacteria and other chemical compounds into your system while also possibly attracting flies. The regulation of ammonia levels becomes challenging, and acquiring dead fish becomes necessary.
Not noticing a dead fish in your tank can lead to two negative outcomes: increased ammonia levels due to decay and the introduction of unwanted bacteria.
Conclusion on fishless cycling
Fishless aquaponics cycling offers a positive aspect as it reduces the time required to prepare the system. Typically, the process lasts 4-6 weeks when fish are involved. However, with fishless aquaponics cycling, it can be completed within 2-3 weeks. This is achievable through the provision of adequate ammonia to promote bacteria growth without any risk of harming fish.
If you cycle your tank without fish, you can easily add as many fish as you want right away. On the other hand, if you cycle the tank with fish, you have to slowly increase the number of fish.
It is now time to introduce your fish into the aquaponics system, but remember to refrain from feeding them for the next 24 hours.
It is acceptable to use ammonia initially, however, once fish are added, it should be discontinued since the fish alone can provide the necessary ammonia source. Only one ammonia source is required.
Nitrite spike
An increase of nitrite levels is frequently observed during the cycling process of a system. Once the bacteria convert ammonia into nitrite, it can become more harmful than ammonia itself.
The establishment period of bacteria that transform nitrite to nitrate is longer in comparison to the bacteria that convert ammonia to nitrite. It is only safe to introduce fish into the water if nitrite levels are at zero. Adding fish when nitrite levels exceed 1ppm may result in their death.
