Purchase starter tomato plants at your nursery or garden center. Although tomatoes are easy to begin from seed, doing this means you must begin in early spring, so the time it takes from planting until you harvest your first ripe fruit will be longer. Large varieties of tomatoes, such as the "Beefsteak" types, take longer to ripen and often produce fewer tomatoes than smaller varieties such as cherry or plum tomatoes.
Combine a gallon bucket full of organic compost or well-composted animal manure with the soil in each planting hole. Dig one hole for each tomato plant you plan to grow. Make your holes the size of a 5-gallon bucket to ensure that the roots of your tomato will benefit from the nutrients when the plants grow larger.
Refill your planting hole with the combined soil and compost or manure, leaving it 2 to 3 inches lower than the surrounding soil. This will create a basin for your plant to grow, making it possible to flood the plant when you water it. Then dig a hole in the center of the recessed area that is slightly larger than the roots of your young tomato plant. If the plant is tall, you can sink it into the soil up to its bottom leaves, which will cause it to grow bushy and not be top-heavy.
Remove your tomato plant from its nursery pot and gently loosen the roots. Set it into your planting hole, spreading the roots evenly throughout the hole. Fill the hole with the soil/compost you dug out and pat it down gently with your hands.
Drive a support stake into the ground about 4 inches from the base of your plant or use a purchased tomato cage. As you drive in your stake or cage legs, avoid your tomato plant's roots. When the plant grows larger, tie it to the stake or cage with nursery tape or cloth strips to support the tomatoes, which can weigh down the plant and fall to the ground, where they are subject to attack from snails and ground-dwelling insects.
Water your tomato by flooding the basin in which it sits. After your plant begins to form fruit, allow the soil to dry before you water it again. If the plant begins to wilt, that's the time to water it, but don't let the soil become too dry. Water your tomato once a week or every 10 days. During very hot, dry weather water more often.
Fertilize your tomato plant with a balanced plant food once before it starts to form flowers. The compost or manure in your soil will nourish your plant when it is small, so wait until about one month after you plant. Follow the label instructions for mixing and applying your fertilizer. After your tomato begins to bloom, help it to make more fruit by using a fertilizer designed for "boosting" blossoms. Such a fertilizer should have a low nitrogen reading, such as 0-10-10.
Control any pests that might be eating either forming fruit or the plant's leaves. Snails and slugs eat tomatoes, especially the ones close to ground level, so if you see them at night, use iron phosphate granules around your plants. Tomato hornworms can be very destructive; if you find any large green worms on your plant, either hand pick and squash them or dust your plant with Bacillus thuringiensis, a natural soil bacterium available at garden stores.