Spring 2009

Tilapia and yellow perch swim under the same roof as tomatoes and salad greens at an innovative urban aquaculture nonprofit organization in Milwaukee. Photo: Carolyn Rumery Betz
Sea Grant Outreach

Milwaukee's Growing Power

Fish and plants grow under the same greenhouse roof

By Carolyn Rumery Betz

Sprouts, spinach, and salad greens aren’t the only things growing under the greenhouse glass at a place called Growing Power on Milwaukee’s north side. Tilapia and yellow perch swim under the same roof as the tomatoes at this innovative nonprofit organization.

Growing Power is on the cutting edge of an urban agriculture movement. Will Allen, chief executive officer, founded the organization 16 years ago and is sharing his knowledge and enthusiasm with groups across the nation and the world. “Everyone wants this system,” said Allen. “People need food now and we can’t wait years for it to happen.”

Allen, who grew up on a farm in Maryland, started the Milwaukee operation by growing vegetable crops on his plot of land and in greenhouses in the city. He also raised tilapia, a fast-growing warmwater fish in three, 55-gallon drums. Over the years, Allen became interested in developing a system in which plants and fish could help support each other, reducing the need and costs for water, fertilizers, and chemical treatments.

At the nearby UW Great Lakes WATER Institute, Fred Binkowski became intrigued with Allen’s aquaculture operation. Binkowski, Wisconsin Sea Grant’s aquaculture outreach specialist, wondered if yellow perch could be raised in such a system. The first collaboration involved setting up a 5,000-gallon tank with 800 market-size yellow perch to see if they could survive. After one year, the successful operation was consumed by all partners during a few Friday-night fish fries.

The current experiment involves raising about 10,000 yellow perch fingerlings and plants together in a uniquely designed three-story recirculation system. This system consists of an 8,000-gallon tank on the bottom for the fish, a middle layer that contains a gravel filtration bed and watercress, and a top layer (about eight feet above the fish) for vegetable plants.

The challenge of the recirculating system is detoxifying the fishy, ammonia-rich wastewater before pumping it up to the potted plants. The gravel middle layer allows bacteria to convert the ammonia to less-toxic nitrates, and watercress provides secondary filtration at this level. The less-toxic water is then pumped to the upper deck, where salad greens are grown in pots filled with compost, worm castings, and coil, a wicking agent that can efficiently deliver nutrients to the greens.

The partnership between UW Sea Grant and Growing Power is also mutually beneficial. Along with the perch, Growing Power has gained Binkowski’s university-based aquaculture expertise. Binkowski now spends about four hours a week at Growing Power, monitoring the fish and water quality.

“Universities haven’t traditionally operated in low-income communities,” Allen said. “The community is getting a tremendous amount of value from the experience Fred brings.”

Binkowski sees urban aquaculture as a new initiative for Wisconsin Sea Grant.

“Aquaculture traditionally takes place in rural settings requiring ponds, wells, and raceways,” he said. “Urban aquaculture can cut transportation costs, create jobs, and take advantage of abandoned warehouses that are cheaper to convert to food production than to condos.”

Both men agree that urban aquaculture can grow and deliver seafood products right where consumers live. Growing Power already markets its fresh fish and vegetables to local farmers’ markets and restaurants and through Community-Supported Agriculture shares.

“We are learning every day how to make this work. It takes a long time to get it right, but the community is ripe for this. We want to build systems to help farmers make a living,” said Allen.

Allen was awarded a “Genius Grant” in 2008 by the John D. and Catherine T. MacArthur Foundation. The $500,000 grant, allocated over five years, will allow Allen to boost his productivity and spread the word even faster.

The Aquatic Sciences Center is the administrative home of the
University of Wisconsin Sea Grant Institute & University of Wisconsin Water Resources Institute.

©2011 University of Wisconsin Board of Regents