The beauty of growing tomatoes in pots is that they're available right outside your door. There are other benefits to vegetable container gardening: you can easily move pots, quickly spot pests and diseases, use limited space such as patio corners and steps, and control the tomatoes' water and sun. Add in some companion plants to your pots, such as basil, cilantro or onion, to increase your harvest.
Terracotta pots will dry out quickly, which means you'll need to water more often. Plastic pots hold the heat and warm the soil, which tomatoes like. If you are growing full-size tomatoes, pick a container that is at least 18 inches wide. Dwarf or cherry tomatoes can be grown in pots as small as 1 gallon. The pot should have drainage holes in the bottom. Add a 1-inch layer of gravel or medium-sized rocks to aid the drainage and keep the tomato's roots from sitting in water.
Dwarf or cherry tomatoes that grow well in pots include Patio, Tiny Tim, Small Fry and Saladette. Determinate tomatoes, also called bush tomatoes, grow to a fixed height, usually between 3 and 4 feet. Good determinate varieties for containers include Patio Hybrid and Pixie Hybrid II. But even indeterminate tomatoes, which grow quite large with long vines, can be grown in containers if the pot is large enough and you stake or cage the plants.
Use a synthetic "soil," the Texas A&M Extension recommends. Rather than regular garden soil, synthetic mixes contain wood chips, perlite, peat moss, vermiculite and other lightweight materials that hold water and nutrients. Texas A&M says you can make your own mix by combining 1 bushel each peat moss and vermiculite with 10 tbsp. limestone, 5 tbsp. 0-20-0 (superphosphate) and 1 cup of all-purpose fertilizer (5-10-10 or 6-12-12). Before adding plants, wet the mix thoroughly.
Because soil in containers dries out more quickly than in the garden, you will need to water your tomatoes more frequently. During the heat of the summer, you may need to water every day. Water deeply, so that excess water flows through the pot's drainage holes. To avoid disease, water in the morning and avoid getting the tomato's leaves wet.
Tomatoes in containers also will need more frequent fertilizing because they have less soil from which to derive nutrients, according to the Iowa State University Extension. Use a liquid all-purpose fertilizer or one made especially for tomatoes every seven to 10 days.