Today I visited Victory Aquaponics in Londonderry, NH, and I was kindly shown around by owner Ross and his very friendly dog Leroy. Before today, I had a basic understanding of how aquaponics works, but I had never seen such a system in real life. In an aquaponics system, fish (in this case goldfish and tilapia) are fed and produce waste in tanks. This waste contains organic forms of nutrients such as nitrogen, potassium and phosphorous, forms that are not yet usable by plants. The waste gets syphoned out of the fish tanks and into other tanks where the waste is broken down by bacteria and turned into plant-available forms of nutrients. When the water reaches the plants, all of the solid waste has been filtered out but the nutrients remain. The plants then extract the nutrients, and the water is ready to be cycled back down to the fish! If the water reaching the plants is deficient in any nutrients, the solution is simply to feed the fish more. Ross is currently growing a range of herbs and greens, as well as cucumbers and peppers—all of which looked super healthy! If he wants to continue growing the last two through the winter he will need to heat the greenhouse. He already heats the water to 70 degrees to keep the tilapia happy and this helps to provide some heat to the greenhouse.
One of the benefits of an aquaponics system is that it uses water very efficiently. In soil-based systems the water evaporates more readily or fails to reach the targeted plants. Ross pointed out that another benefit of aquaponics is that it makes farming possible in locations where soil quality is very poor.
I was especially interested in learning more about aquaponics because I had just heard about an existing debate over whether or not aquaponic and hydroponic systems should be eligible for organic certification (up until this point, they HAD been eligible). Basically, the basis of the argument against eligibility was that “organic” is defined by the use of practices that nourish the soil, and since there is no soil in aqua/hydroponics, it cannot possibly qualify. Ross argued that even in a soil-based system, plants are extracting nutrients from the water. In my view, whether or not a farm is organic depends on the nature of the fertilizers that are introduced to the system, as well as the stability of the system. This past fall, the National Organic Standards Board voted against the proposal to keep aqua/hydroponic farms from being included in organic agriculture. So, farms like Ross’ are still up for organic consideration!