Homegrown tomatoes taste sweeter than store-purchased ones. This warm-season perennial lasts only for the summer in the United States, where cold weather limits the growing season. Growing tomatoes in containers allows the gardener to move the plants into a protected area to avoid the cold.
Drill at least four holes in the bottom of the container if it does not have any drainage holes. Tomatoes need at least a 20-inch container. Larger tomato varieties need larger pots. Wash the container in soapy water. Rinse with 1 part bleach and 9 parts water to eliminate any pests and plant disease.
Mix equal parts sphagnum peat moss, potting soil, perlite and manure. This mixture drains quickly, holds moisture in the soil and provides the tomato plants with nutrients.
Fill plant pot with soil mixture, leaving about 2 inches of space between the soil level and the rim. Mix in 10-10-10 slow-release fertilizer. Add 1/2 tbsp. of fertilizer for every gallon of soil mixture. A 20-inch container holds about 6 1/2 gallons of soil, so you would add 3 1/4 tbsp. of fertilizer.
Dig a hole in the center of the pot as deep as the first two leaves on the tomato stem with a hand trowel. Place the tomato plant in the hole and fill with soil. Firm the soil around the stem. The buried stem will produce more roots.
Cover the top of the container with 1 inch of sawdust, straw, pine needles, grass clippings or shredded bark mulch. This retains moisture and moderates the high summer temperatures.
Place a tomato cage around the seedling. As the plant grows, rest the branches on the cage bars. Water the top of the container until it runs out the bottom of the pot.