Cathy Rehmeyer is a master gardener who grows over a ton of food on one-tenth of an acre each summer, and she has some tips for urban gardening. “First, focus on soil health,” she says, and let your child help you dig compost into the soil. Choose compact plants, such as determinate cherry tomatoes instead of sprawling heirlooms. Grow citrus fruits, dwarf apples or cherry trees in large pots. Take advantage of vertical space—plant pole beans instead of bush beans and train them up a bamboo teepee.