At their Milwaukee site, Growing power had several interesting systems on display. Among these were the aquaponics systems that grow both fish and vegetables simultaneously and symbiotically. Fish are grown below the vegetables in a large tank of water. The water is cycled by pump from the fish tank to a gravel bed where beneficial bacteria break down the ammonia from the fish and convert it into nitrate and then to nitrogen. From the gravel bed the water is passed through a raised growing bed where the nitrogen is used to feed the plants. The water then returns to the fish tank and the cycle repeats. Both the fish and the vegetables are sold to restaurants and markets.
Growing Power is also big into compost. They say they collect over 100,000 pounds of waste per week for their compost. Major donors include Alterra coffee who supply Growing Power with used coffee grounds, as well as local breweries who supply spent brewing grains. The mixture is massed into large piles and composted in different places. Heaped in the corners of a hoop house the heat from the compost alone keeps the space above freezing. Piled along the outside of a greenhouse, the compost is used to culture worms. Lots of them. Though the air was temperature was well below freezing, turning over a clod of compost reveled a steaming mass of worms. And this is something Growing Power says ‘they’ said couldn’t be done in a Wisconsin winter.