Select a location for the tomato plants. Choose a location that gets plenty of sunlight, with some protection from wind. The area should also be a well-draining area to prevent the roots from rotting.
Assess the soil in the area where you plan to plant the tomatoes. Determine if the soil is sandy or clay. If it is, mix into the soil about 2 to 3 inches of compost or another organic material to improve the quality of the soil.
Purchase the tomato plants. You'll find several varieties, including full-size tomatoes, cherry tomatoes and grape tomatoes. Within each different types of tomato you'll find several varieties. If you're unsure which variety to purchase, ask the plant nursery staff for suggestions that work well in your climate.
Place the tomato plants outside during the day in shade so they become accustomed to the outdoor climate. Placing them in the shade prevents them from getting sun damage. At night, bring the plants inside to protect them from the cooler temperatures. Move the plants to more and more sunlight every two days. The entire process of acclimating the plants will take between seven and 10 days.
Dig a large hole in the selected location for the tomatoes using a shovel. Place the tomato plant in the hole, and cover it with the displaced soil. You want the roots and part of the stem underground, with only the top leaf cluster left out. This allows more roots to grow for a stronger root system. Water the plant immediately.
Add growing aids around the plant. If you use a stake, drive it into the ground about 3 to 4 inches from the plant. Loosely tie the plant to the stake with a soft cord. Retie as necessary as the plant grows. To use a tomato cage, put it over the plant pressing it into the ground. To make a trellis, place two sturdy wooden posts on both sides of the plant, with a durable wire stretched between the posts. Tie twine to the wire and to the base of the plant. Wrap the plants around the twine for support as they grow.
Check the soil frequently to make sure it stays moist. Water the tomato plants at least twice a week so the soil is soaked to about 6 to 8 inches deep.
Wait until the ground reaches 65 degrees F and then mulch to the tomatoes. Placing the mulch when the ground is colder doesn't allow it to warm up as quickly. Straw is ideal as a tomato mulch, but grass clippings or dried leaves also work. Leave about an inch circle around the stem of the plant uncovered. The mulch helps retain moisture, especially during the hot summer months.