The 1989 Loma Prieta earthquake left many of San Francisco's urban freeways structurally unsound. (Back then, there were many, carving up the core of the city.) But the flipside was a boon: The teardown of broad segments of elevated road has led to the revitalization-the reinvention, really-of neighborhoods like Hayes Valley. It has also given the city chunks of unused space, including the stretch between Laguna, Octavia, Oak, and Fell Streets, where ramps to the old Central Freeway haven't led anywhere in years.San Francisco plans to develop this lot eventually, probably with mixed housing and green space. But a clever new project has been conceived for the interim years: an urban agriculture cooperative called the Hayes Valley Farm. "The Hayes Valley Neighborhood association contacted the Mayor's Office of Economic and Workforce Development to 'activate' the lots," says Chris Burley, now the project's director. Agriculture was the idea that moved everyone. "We've all seen the power of gardens to transform a space," he says.First, they had to transform some soil. Raising crops around an ex-expressway has meant thorough testing of the ground to ensure safe lead levels (all but one patch of the site have passed), and extensive layering of organic matter. But now they're off and planting. "[We've] potted up one hundred and fifty fruit trees which will be available for sale to homeowners around the Bay Area," Burley says. "We are also planning on growing vegetable starts in a greenhouse."As importantly, residents have gotten the chance to work their own urban acres. Much of HVF's labor happens at "work parties," where locals-including young students-learn farming skills and something like the value of tilling with a neighbor. When Burley comments, "at this stage we are allowing things to grow organically," it's interesting to realize he's talking about the community, not the crops.