The struggle for gardening space in small yards has led to a surge of interest in vertical growing techniques, including the frequent practice of planting and growing tomatoes and cucumbers upside down. This space-saving technique also eliminates common pest problems found in garden soil and provides superior drainage, air flow and sunlight. Buckets and bags can be converted into upside-down containers with a 2-inch hole cut or drilled at the base. Newspaper, straw, coffee filters and similar substances pushed around the holes prevent soil and plants from falling out through the hole.
Fruits
Strawberries are commonly grown upside down in containers. These relatively small plants give exceptional yield because you might also cut extra holes to fill out the containers with strawberry plants on all sides. Pick everbearing strawberry varieties that make fruit in many spurts. June-bearing strawberries produce all their fruits at once, which could put too much strain on the plant. Grapes may also develop upside down, but the upside-down container should be set near a trellis to support a number of the burden of creating grapes. Compact lowbush blueberries would be suitable candidates for upside-down containers but U.S. Department of Agriculture plant hardiness zones 8 through 10 don’t provide the necessary chilling time. Adventurous gardeners might try manipulating the cold period in a fridge over winter.
Vegetables
All kinds of peppers can be increased upside down, including sweet onions and hot peppers, but bigger bell peppers may need to be picked when small. As with tomatoes, bury as much of this plant stem as you possibly can to ensure a strong root system. You can develop eggplants upside down, but you ought to harvest fruits when they are little or pick Japanese eggplant varieties that are much more compact than their Western counterparts. Zucchini and summer squash do nicely in upside-down containers, but you have to harvest the fruit while little so big heavy fruits don’t damage the plant. Instead of installing a trellis for pole beans, then you can develop them upside down; bush beans may also develop well in upside-down containers.
Herbs
Hang your own herb garden right outside your kitchen window. With a growth habit like tomatoes and peppers, basil, parsley and lemon verbena make handy choices for upside-down gardening; pinch and harvest the leaves often to encourage bushy growth. Creeping herb crops, such as oregano and thyme, also do well when grown upside down. As with strawberries, you can plant herbs at the top and sides to fully cover the container with foliage.
Inedible Plants
As a general rule, if a plant may grow in a container, then it may similarly grow in an air-tight container. Petunias (Petunia x hybrida) and also their relative trailing petunia (Calibrachoa x hybrida) are among the easier flowers to develop. Semi-trailing nasturtiums (Tropaeolum small) hang down 2 to 3 feet in the container, but you may also grow bushy, dwarf nasturtiums. If you prefer green foliage to bright blooms, consider common houseplants such as golden pothos (Epipremnum aureum) and heartleaf philodendron (Philodendron scandens). You can even plant a sprouting sweet potato (Ipomoea batatas) upside down in a container, allowing the twining vines to spill out through the hole.