If it were up to Will Allen, low-income urbanites would be cultivating fresh fruit, vegetables, and fish in community centers, in empty lots, even on their own rooftops. "People don't realize that cities originally produced the food," says Allen, an urban-farming expert who has pioneered a local-farming movement. Rather than bringing people back to the land, Allen's methods of growing food and teaching urban cultivation are transforming the way low-income families can get safe, affordable meals. "Obesity, diabetes, and inadequate nutrition are increasing at an alarming rate, especially for the poor and people of color," he says. He considers it a civil rights issue. "I'm interested in creating a more just food system. How do we get the same food to all people?"

Allen's Growing Power is a nonprofit complex of teaching farms that raise vegetables, fish, livestock, and honeybees year-round using cheap, replicable, innovative techniques that staffers develop themselves. At his main facility in Milwaukee, Allen is constantly working to perfect methods such as aquaponics -- which uses the runoff from tilapia tanks to nourish plants -- and an elaborate composting scheme that provides heat to the greenhouse; all of these techniques find their way into an expanding network of urban-farm projects around the country.

Creating a "community food system" has the added benefit of taking some pressure off the earth. Says Kevin Fitzsimmons, a professor at the University of Arizona's College of Agriculture and Life Sciences: "Aquaponics and greenhouse vegetable production appear to be the best model for intensifying agriculture with minimal impact on the environment." What Allen has done, Fitzsimmons says, is prove it's scalable. "Will Allen has demonstrated the practicality and educational potential of these systems."

After a brief career in professional basketball and then corporate America, Allen took a leap back to the future in 1995, when he used his life savings to buy the last working farm in the city of Milwaukee, a 2-acre ruin of fields with a broken-down greenhouse. It was a lifestyle thing. "I grew up on a farm, and I wanted that same life for my family," he says. When asked to help some local kids with a neighborhood garden, Allen began using his farm as a teaching center. Kids and adults -- many black, poor, or immigrant -- gravitated there to volunteer, hang out, and learn. He began holding workshops on urban gardening, eventually adding a restaurant-grade kitchen and retail shop. Today, Allen's farm serves more than 50 local restaurants, creates sustainable cafeteria programs for local corporations including Rockwell Automation and Kohl's, and distributes low-cost food to more than 10,000 families. "Because we grow, process, and distribute, we can teach other people how to do so as well," he says. Growing Power now has six facilities in Milwaukee and Chicago, and has opened eight regional training centers, from Mississippi to Massachusetts. Some 35 staffers are juggling more than 70 short- and long-term programs around the world.

In 2008, Allen was awarded a MacArthur fellowship for his work. He is pouring his $500,000 grant into food-policy research, a book project, and scholarship programs. "We're not just growing food, we're growing people, too," he says. Most recently, he was the subject of an Internet campaign to draft him into service as the official White House Farmer. A nice gesture, Allen says, but a kitchen garden -- even at 1600 Pennsylvania Ave. -- wasn't enough to turn his head. "They really need a 5-acre farm and local people working it. I could definitely help them train the right person to run that." -- by Ellen McGirt