We’ve had a rather hard spring—to be honest our hopes for a wonderful spring harvest from the greenhouse were dashed when we discovered a major fish problem that set us back to square one. Of course, fish are the engine of aquaponics—they provide the fertilizer that feeds the nitrifying bacteria that feeds the plants (read more about aquaponics). Without the fish we were dead in the water (pun intended) for several weeks. Our lettuce refused to grow, and everything we tried to grow turned yellow for lack of nutrients. We figured out how to feed the system with hydroponic nutrients, but nothing is as good as fish for making plants grow. The problem, we finally realized, was system design. Our fish tank was too small for the amount of plants that we have—plants that demand a huge amount of nitrogen and other nutrients. The solution was to add a second fish tank. No small task, but we couldn’t think of any other way to add more water volume and fish capacity.
Finally we have reopened the tanks and restocked. We now have two fish tanks, one full of hundreds of goldfish, and one with a few dozen tilapia. We’re still having issues with the tilapia, but the goldfish seem practically indestructible. At $0.15 each, goldfish are a real winner.
It’s amazing the difference the fish made. As soon as the fish hit the tank, plants started to grow again. You’ll see some pictures below of our lettuce growing in the raft. I can’t believe how good this lettuce tastes. It’s crunchy and juicy and sweet; I am amazed. After a tough start, spring is starting to look up!