We are going to start a new series of articles on Permaculture practices from the letter a to z, with one topic being covered for each letter. So starting with the letter a, we are going to cover aquaponics. By no means with this be a complete list of topics, but it should be interesting for you to see all the topics this way and it will make it a little more challenging for me to develop topics for all of the letters. Let me say that all plants that we discuss will be based on the Northwest Ohio, so you may use them directly in your gardens around the Lima area all the way up to Toledo Ohio.
Aquaponics is the combination of aquaculture and hydroponics, which simply means growing fish and plants in a single system. In previous articles we discussed window hydroponics systems, so you have a basic knowledge that the hydroponic system provides the plants with a nutrient rich liquid that can be absorbed easily by the plants root system. If we add fish into the system, we find that the fish will provide ammonia rich waste water which the bacteria in the plant grow bed breaks down into nitrites and then nitrates. Consequently the plants use the nitrates as nutrients for growth, the bacteria and grow bed medium purifies the water, and oxygen enters the system from the use of the circulating pump, purifying and oxygenating the water so the fish can start the process all over again. Think about it, you can harvest vegetables, fruit, and herbs all winter long along with fresh fish. Yes, you can eat the fish also depending on the variety you select. I personally like bluegill and white perch because they like colder water temperatures, but many people like raising tilapia due to their light texture and flavor. Tilapia like a warmer water temperature around 78 degrees which can be maintained if placed inside a heated area such as a greenhouse or heated living space. But cooler living areas such as a garage or basement can be used with the addition of LED or fluorescent grow lights. Depending on the size and materials used, many home systems are placed outside during the warmer months, then moved indoors during the colder months to continue taking advantage of the system year round. It is possible to grow various plants to feed your fish reducing any expenditures you would have for commercial fish food, duckweed is one you will hear a lot about. A smaller tank on the side can generate enough duckweed for your entire system as it regenerates so quickly.
Small aquarium pumps can be used on apartment sized systems, larger systems with stock tanks, barrels, and large tanks will be sized proportionately for the flow requirements and distance that the water must be pumped vertically to supply the plants. Systems can be as small as a 10 gallon aquarium tank to over 10,000 gallons on farm scale systems. Continuous circulating systems are the easiest to build, but this means that the roots of the plants will always be immersed in the water providing the potential for unwanted bacterial growth. Because of this many systems will allow the growing medium to drain for a period of time by turning the pump on and off or by filling the growing medium reservoir, then allowing it to drain back into the fish tank, then starting to fill the reservoir again. This type of system is normally regerred to as a flood and drain system.
With a little research you will find that there are many plans available for download or you can purchase the entire kit ready to assembly complete with instructions and telephone tech support. Take a look at the DIY systems at http://www.friendlyaquaponics.com/ to help you with sizing your system. And as always feel free to contact me directly with questions you might have.
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