"You bring a plant or garden-related item and you get an item that you like" explains Diane Olesik who has been coming to the Northwest (Philadelphia) Gardeners Association plant swap for several years. After attendees get a paper ticket for each plant they've brought and stage their plants at the designated tables – annuals, sun perennials, shade perennials etc – they hover by the plants they want to take home. Then they spring into some elbowy action when the countdown teaches "…zero- Go!" Cathedral Village, Roxborough, Philadelphia, Pa. Watch video here