Tomatoes grow best in average to rich garden soil with a pH of 6.5-6.8. They prefer nighttime temperatures 55-65 degrees F and daytime temperatures 75-85 degrees F. Determinate tomato plants grow to a certain height and fruit over a short period of time. Indeterminate tomato plants continue to grow and produce fruit over the entire growing season. New varieties of tomato plants are resistant to many of the pest and disease problems that affected tomato growers in the past. Tomatoes prefer full sun and can be grown anywhere the temperatures are sufficient for at least 75 days.
Find an area of the garden that gets at least 6 hours of sun each day for your tomato garden. Tomato plants should be spaced 36 inches apart, unless they are patio tomatoes to be grown in a pot, so be sure the area is of sufficient size.
Clear area of weeds and break up the soil to a depth of 18 inches. Add 3 inches of well-rotted compost and work into the top 12 inches of soil. Adding organic matter will greatly enhance the soil's ability to hold moisture and helps break up heavy clay soil. Build or set up trellises or cages where the tomato plants will be planted.
Plant tomato plants on their side and at an angle where the roots are 6 inches deep and the main stem angles to the surface of the soil. You can cover up to 80 percent of the stem with soil. Don't plant straight up and down, because most of the nutrients and fertilizers are in the top 6 inches of soil. Planting at an angle will help the plant produce a sturdier stem. It will produce roots from the part of the stem buried in the soil. The top will eventually curve upward and grow upright after a few days.
Fertilize with a fertilizer specific to tomato plants. Follow the fertilizing schedule and amount recommended in the instructions on the fertilizer container. Tomato plants need fertilizer from the time they are planted through the fruiting period.
Spread mulch 1 inch deep in an area 24 inches wide around base of tomato plants. This will keep the roots evenly moist and prevent water from splashing on the leaves. Splashing water is a source of fungal and bacteria spores that can create serious problems on the tomato plants.