Aquaponic Systems for Homesteaders
How Does Aquaponics Work?
Reading Time: 5 minutes
By Anita B. Stone – Aquaponic systems could be a top-notch method of gardening for homesteaders. Why? Because it is a simple agricultural system that can be placed almost anywhere: in your backyard, in a greenhouse, or indoors. And it operates through a completely natural process that mimics the functioning of lakes, rivers, and other natural waters.
Aquaponics is an integrated, combined plant and fish system where one element benefits the other. The system utilizes both aquaculture and hydroponics, which when combined, results in a symbiotic process that builds an effective nutrient exchange very much the same as in any natural ecosystem.
The general concept for the construction of an aquaponics system is not complicated and is open to many different configurations, depending on the intent and scope of the builder.
Simply put, the four primary components are fish, water, bacteria, and plants. Fish are placed in a fifth component — a water container — where their byproducts interact with bacteria, which transform the waste into plant-available nutrients. The water is then provided to plants and the plants, in turn, help clean and revitalize the water to be safely returned to the tank. Plants grown in this cyclical arrangement use 90% less water than those raised in traditional systems and grow three times faster than is characteristic of other gardening methods. The result is a highly flexible, self-contained, and productive system, with the best part being that you get to harvest both fish and plants from one garden, all without the use of artificial fertilizers or pesticides.
Construction of any of the possible types of systems requires specific information depending on which fish are chosen, their requirements, the type and size of the tank, and the irrigation method. In one commonly used system, after the fish are established, plants are placed in a “growing bed” which is elevated above the fish tank, usually on a flat board. The growing bed is filled with a growing media, which supports the plant structure and aids in keeping the water clean.
This media can be of several types, such as expanded shale, coconut fiber, rice husk, perlite, clay pebbles, lava rock, or other available substances. The tank water can be carried to the plants by hand, or in larger operations through a connection of pipes with the installation of a pump. The water returning to the tank is automatically rejuvenated by the activity of the plant roots as they remove nitrogen from the water, as well as by the filtering action of the growing medium.
Aeration of the water occurs as it flows through the medium and the air space before returning to the fish via gravity or by pump action.
Except for the addition of food for the fish, aquaponics is a closed system where the water can be recirculated indefinitely, needing only to be topped off when evaporation and transpiration from plants lowers the level. Aside from the above description, known as the “media-filled bed system,” there are numerous other possible arrangements.
One method is a vertical design which allows a large amount of food to be grown in a small space. In this design, plants are stacked on top of each other in a tower system and water from the tank is pumped to the top and flows through wicking material from which plants absorb water and nutrients.
Another frequently used design uses rafts, in which several platforms made of tubing float on top of the fish tank. Plants are singly placed in cups on the tubes through which water from the fish tank is piped. Roots from the plants dangle in the water to be bathed and fed. In this system, roots are only partially submerged, leaving room for aeration. A healthy pH level in the aquaponics system is 6.7 to 7.0.
Although some technical issues, such as water pH need to be monitored, the system is a highly flexible, “self-cleaning” solution to growing plants.
An aquaponic system offers numerous designs since the general theory and primary components can be assembled to suit individual circumstances and purposes. Additionally, the components do not need to be purchased as specifically made for such a system; fish tanks, for instance, can be made in any size, preferably round to facilitate circulation of waste, or of any material such as plastic tubs, glass fish tanks, barrels, or even non-waterproof containers lined with plastic pond-liner material.
A single tank can be used or several smaller ones. Placement of tanks can be indoors or out; if placed outdoors, a south-facing location with at least six hours of sunlight is required.
Greenhouses are handy because of temperature control and protection from intruders. If the tank is indoors, a grow light for both the fish and plants plus a heat source will be necessary.
Occasionally, a permanent base can be made for the tank to keep it stabilized and firmly in place. The fish require specific conditions to survive and thrive. If chlorinated water is used, wait a week before introducing the fish to allow the chlorine to dissipate, and an average of one fish per 10 gallons of water is recommended to give the fish room to circulate. If an outdoor area is used, the fish can be stocked as soon as the outdoor temperature reaches 70 degrees F.
Use disease-resistant fish that fit your needs and space. You can use ornamental fish such as Koi or goldfish, tilapia, or game fish such as bass, catfish, and bluegill. Trays for planters are easily obtainable, either re-purposed, made from household plastic containers, or bought from fish specialty enterprises.
Ideally, any of the planters in aquaponic systems should be six to 10 inches deep much like raised vegetable beds. The establishment of beneficial bacteria will occur naturally but will require a few days of circulation to become adequate for the system to be self-functioning. An aerator may be needed for larger projects.
In conclusion, aquaponic systems are remarkable in that they are a closed system that conserves water, is organic, and closely mimics a natural ecosystem, requiring only that the fish be fed. A little research on the internet, reading fish books, or speaking with fish experts can help avoid unnecessary oversights. For some fish, such as tilapia, food like duckweed can be homegrown. Make sure the water level and a healthy balance of components are checked regularly.
Aquaponic systems are cost-effective, with no waste and no need for harmful chemicals. Growing leafy greens, lettuces, and herbs are great choices for new aquaponics experimenters, and a small system, watered by hand, can be set up in a kitchen or bedroom. Where there is light, every homesteader can participate in a rather miraculous homemade ecosystem’s functioning and enjoy all the products as a result.
Have you tried aquaponic gardening? What types of aquaponic systems intrigued you the most and which ones have you tried? We would love to hear from you in the comments below!
Originally published in the March/April 2022 issue of Countryside and Small Stock Journal and regularly vetted for accuracy.