Start the tomato from seed indoors six to eight weeks before the average last frost date. Or purchase a seedling just before transplanting outdoors. Look for a sturdy dark-green plant, 6 to 10 inches tall. Avoid a stressed plant with yellow leaves, spots or aphids. Do not buy a flowering or fruiting plant, because it will not get much bigger.
Prepare a planting site that receives at least eight hours of sun. A tomato plant requires well-drained and slightly acidic soil, so till compost into the soil to improve drainage and fertility.
Dig a planting hole 2 inches deeper than the container's depth. Remove the tomato plant from the container, and place it in the planting hole. Backfill the soil until it is level with the leaves. Tamp to firm, and stake or cage indeterminate plants.
Spread a 3- to 4-inch layer of mulch around the plant a month after planting. Organic mulch, such as dried leaf clippings or straw, retains moisture and suppresses weeds.
Check the moisture of the soil with your finger, and water as necessary. The amount of water a tomato plant requires depends on the cultivar, soil condition, growth stage and weather. Use a soaker hose to water the tomato plant evenly.
Apply fertilizer to the plant when it is about 1 foot tall. Mix a solution of 2 tbps. 10-10-10 or 5-10-5 fertilizer to 1 gallon of water, and pour it around the base of the plant. Repeat the application at the time of flowering, if necessary.
Check a staked, indeterminate plant regularly for suckers, or the side branches that form in the joints where leaves join the stems. Pinch off suckers just beyond the first two leaves that develop. Do not prune a determinate tomato variety.
Pick the tomato as soon as it reaches peak cultivar color and size. Apply slight pressure with your thumb to the spot where the calyx joins the stem, then twist the fruit off. Store your perfect tomato in a dark, warm area to ripen.