Grow tomatoes in a bucket by drilling holes in the bottom to allow for drainage and using light potting soil. If you have a 5-gallon bucket, add half a dozen 1/2-inch holes. For tomato plant varieties that grow up to 4 feet tall, use a bucket that is a minimum of 18 inches deep. Determinate tomato plants are the best choice for bucket gardens as they only grow up to 2 feet tall
After adding drainage holes, combine potting soil, perlite and peat moss, and add it to the bucket. Place the plant's root ball all the way up to the top set of leaves in a hole in the soil, and tamp it gently down around the stem. Water the seedling well until water seeps from the drainage holes, and feed the plant with water-soluble fertilizer. Fertilize the plant regularly every two weeks.
Place the bucket in an area that receives plenty of full sunlight each day. If using indeterminate tomato cultivars, which grow until a killing frost, add a trellis or stake to the bucket to support the plants. Water the plants regularly once the top 1 inch of soil starts to feel dry. A lack of water manifests in wilted foliage or blossom drop.