Everyone loves garden-fresh vegetables, but who has the time or energy to grow their own? You do--if you adopt Tom and Marty's tried-and-true schemes and tricks for 20-minute vegetable gardening.    They'll help you create from scratch a ready-to-plant garden in less than two hours, and then help you choose the easiest, most rewarding plants for your region and your tastes. You'll learn tips for winning the neighborhood tomato contest and how to turn a stack of old tires into an heirloom potato patch. Discover the perennial vegetables you plant once and harvest for years, and claim as your own the recipes for Brighton Beach borscht, Japanese radish pickle, and sweet- potato pie. Encouraging, practical, and always unexpected, The 20-Minute Vegetable Gardener means liberation for home growers everywhere.