Gardeners often find that growing tomatoes upside down appears to cut down on leaf blights and molds created by rain splashing up from the ground and transmitting disease. Upside-down tomatoes can also be grown to take advantage of vertical space, such as might be found under a deck or its staircase. While they are not easily portable by one person, a careful gardener and an assistant can move them to take advantage of shifting sun as the seasons pass.
Cut a 3-inch hole in the bottom of the bucket. Cover the hole with a coffee filter or garden fabric.
Fill the bucket to the very top with potting soil. Stir in water crystals for better retention of moisture in hot climates. Moisten the soil. Snap the lid on.
Turn the bucket upside down. Cut a X-shaped slit in the coffee filter or garden fabric.
Plant a tomato plant in the hole in the coffee filter or fabric in the bucket. Use your fingers to create an opening for its root ball. Try to bury about 1 inch of the stem as well under soil to stabilize the plant.
Allow the plant to grow for two weeks normally so that it becomes established.
Hang the tomato upside down on a sturdy S hook from a ceiling or balcony. The bucket itself will actually be right side up. You may want an assistant as the bucket can be heavy and you want to avoid dropping it and harming the tomato plant.