Farming With Fish at Growing Power
Thursday, December 10, 2009 at 7:30AM 
On Tuesday I wrote about the composting operation at Growing Power; today I'd like to focus on the aquaponics technology - the combination of aquaculture and hydroponics - used at the farm. We've covered aquaponics on this site before, when Dorothee and I went down to Flanagan, IL and made a video about an aquaponic farm called AquaRanch. At Growing Power they do some things similarly to what we saw at AquaRanch, but most of they're setup is very different.
At AquaRanch, Myles Harston keeps the fish in large, circular tanks that are located in a separate room from the vegetable grow beds, and he runs the waste water from the fish tanks to the grow beds. At Growing Power, space is utilized more efficiently. The fish at Growing Power are kept in long, 4-foot deep rectangular tanks that have been dug into the ground. One benefit of this design is that the ground helps to insulate the fish tanks, and it leaves more vertical space to build grow beds (and the Growing Power folks use every square inch of that extra space).
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When I visited, we actually saw some workers building a new aquaponics bed (above, at left). My tour guide told us that the materials needed to construct one of the beds only costs about $4,000, with the fish tank liner accounting for most of the cost.
Above the fish tanks, the Growing Power folks have rigged a two-tiered shelf system that serves as grow beds. The water from the fish tanks, which is loaded with fish waste that's rich in nutrients and microbes, is pumped up to the elevated grow beds. The grow beds are set at a slight angle, so the water flows slowly from one end to the other. One of the most common plants grown in these type of bed is watercress (pictured at top), because it likes a lot of water and it does a good job of filtering and cleaning the fish water.
At Growing Power they use both tilapia and yellow perch in the aquaponics systems. Yellow perch are native to the Great Lakes, so they can handle cold water, but tilapia are tropical fish, so their tanks must be heated. Unlike AquaRanch, where the fish are harvested and filleted on-site, Growing Power only sells whole fish at present, but at $6 per pound it's a bargain compared to AquaRanch's $15 per pound tilapia fillets.
-Mark
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Reader Comments (2)
It is so beautiful to see that people still care for nature fish and farming is what keeps our environment clean and green
We need to give value to the green world around us fishing and greenary are two things that help our environment