What if I told you that you could catch fish for dinner right in your own backyard? And if you did, what if I told you that right up until you caught those fish, they were growing the veggies for the rest of your dinner? Would you believe me? You should! This is all within reach using a new style of gardening called aquaponics.
Aquaponics is, at its most basic level, the marriage of aquaculture (raising fish) and hydroponics (growing plants in water and without soil) together in one integrated system. The fish waste provides organic food for the growing plants and the plants naturally filter the water in which the fish live. The third and fourth critical, yet invisible actors in this symbiotic world are the beneficial bacteria and composting red worms. Think of them as the Conversion Team. The beneficial bacteria exist on every moist surface of an aquaponic system. They convert the ammonia from the fish waste that is toxic to the fish and useless to the plants, first into nitrites and then into nitrates. The nitrates are relatively harmless to the fish and most importantly, they make terrific plant food. At the same time, the worms convert the solid waste and decaying plant matter in your aquaponic system into vermicompost.
Any type of fresh water fish works well in an aquaponic system. Tilapia is perhaps the most widely grown aquaponics fish, but aquaponic gardeners are also growing catfish, bluegill, trout, and even red-claw crayfish. Not interested in eating your fish? No problem! Koi, goldfish, and any decorative fresh-water fish you would purchase from a pet store work as well. In selecting your fish, however, you do want to pay attention to the temperature at which they both thrive and survive. Tilapia, for example, can survive down to temperatures in the low 60s, but they won’t thrive until they reach the mid 70’s. In contrast, trout will survive up to a maximum temperature of 65, but won’t thrive until their water is in the high 40s to low 50’s.
There are also only a few limits to the types of plants you can grow in an aquaponics system. In fact, the only categories of plants that won’t thrive in an aquaponics system are plants like blueberries and azaleas that require an acidic environment to thrive. This is because aquaponic systems stay at a fairly neutral pH and therefore are a poor environment for plants requiring a pH of 4.0 – 5.0.
So can all of this work in any climate? Absolutely…with some protection. A backyard greenhouse is ideal because not only can you create an ideal environment for your fish and plants, but the sunlight is free! As an added bonus, all the water in the fish tank, sump tank and grow beds creates thermal mass in your greenhouse which helps moderate temperature extremes. If you aren’t fortunate enough to have a backyard greenhouse, you can also grow inside. Many aquapons have dedicated their garages and basements to their aquaponics systems!
Here is the rest of the good news about aquaponics:
Aquaponic gardens are straight forward to set up and operate in your own backyard or home as long as you follow some basic guidelines. They can even be constructed using recycled materials, including old bathtubs and commercial containers used to ship liquid foodstuffs. Or purchase a system kit if you are not very DIY-inclined. The main point is to set up a system soon and become fish independent! There is simply no reason to rely on the fish counter anymore.
Sylvia Bernstein will present a workshop at the Puyallup, Wash. 2012 MOTHER EARTH NEWS FAIR.