On Saturdays and Sundays at this time of year, Minnesota farmers begin taking to the streets, transforming vacant city blocks into gardens of earthly delights. All summer long, even the most brown-thumbed city dweller can feast on heirloom tomatoes and corn picked early that morning, so sweet it is sampled off the cob. And there is no better showcase for locally grown produce and artisan food than the downtown branch of the St. Paul Farmers' Market, located at Fifth and Wall streets. This market, the oldest of its kind in the Twin Cities, has always been a seedbed for new influences and ethnic diversity: exotic Hmong peppers, gnarled gourds, delicate squash blossoms, teeny potatoes, lemongrass, lotus root, and every variety of basil--plus organic meats, sausage, cheese, eggs, artisan breads, honey, maple syrup, and even chocolate. The market's Minneapolis counterpart is laudable in many respects, but only St. Paul requires that all of its vendors be local. Many are certified organic or use sustainable growing methods. The market boasts numerous satellites in and around the city; see the Web site for details, and for updates on the ongoing search for a year-round indoor home.