Make your farmers' market goodies last three to four days longer by creating your own produce bags. Use a pin to poke holes in a zip-top bag (about 20 holes per medium-size bag). When air flows through, it prevents the build-up of carbon dioxide, which in turn, slows the ripening process, says nutritionist Cathi Lamp of the University of California-Davis. Another stay-fresh tip: Don't peel or wash your produce until just before eating or cooking. The outer layer offers extra protection against spoilage.