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Tomato Growing Guide

Tomato plants are tender, warm-season crops that thrive in full sun and cannot tolerate frost. It's crucial not to plant them too early. In most regions, tomatoes should be planted outdoors in late spring or early summer when the soil has warmed sufficiently. However, in zone 10, they are best grown as fall and winter crops.

Tomatoes require 40 to over 100 days to mature, depending on the variety. Due to their long growing season, most gardeners opt for small starter plants or transplants rather than seeds once the weather has warmed up in spring.

Guidelines for selecting and planting transplants:

  • Choose young tomato plants from a reputable nursery.

  • Opt for plants that are short and stocky with dark green foliage and sturdy, straight stems about the thickness of a pencil.

  • Avoid plants with yellowing leaves, spots, signs of stress, or flowers and fruits already forming.


  • Select a sunny site with 8 to 10 hours of direct sunlight per day in northern regions. In southern regions, light afternoon shade (natural or provided, such as with row covers) can be beneficial.

  • Prepare the soil by digging it to a depth of about 12 inches and incorporating aged manure or compost. Allow two weeks for these amendments to integrate before planting.

  • Avoid planting tomatoes (or related crops like eggplants, peppers, and potatoes) in the same location where they have grown in the past two years. Rotate crops to prevent diseases and soil nutrient depletion.

When to Plant

  • For seed starting indoors, sow tomato seeds about six weeks before the last expected spring frost date in your area. Plant seeds 1/2-inch deep in small trays. Transplant seedlings outdoors approximately two weeks after the last frost date when temperatures consistently stay above 50°F at night.

  • Direct-seeding in the garden is possible if the soil temperature reaches at least 55°F, with optimal germination occurring at around 70°F.

Hardening Off

  • If you're transplanting seedlings, acclimate them to outdoor conditions over about a week before planting. Begin by placing them outdoors in a shaded spot for a few hours on the first day, gradually increasing their exposure to direct sunlight each day.

How to Plant

  • Transplant seedlings into the garden after all danger of frost has passed and the soil temperature reaches at least 60°F. Refer to your local planting calendar for recommended transplanting dates.

  • Install tomato stakes or cages at planting. These support structures keep the developing fruit off the ground, reducing disease risk and keeping the plants upright.


Water tomatoes in the early morning to ensure they have enough moisture for the day ahead. Initially, water newly planted seedlings or transplants generously. Once established, provide about 2 inches of water per square foot per week, watering deeply to encourage strong root growth. Avoid overhead and late afternoon watering to prevent leaf diseases.


Prior to planting, work compost into the soil and add bone meal or organic tomato fertilizer to the planting hole. Avoid high-nitrogen fertilizers that promote foliage growth at the expense of fruit production. Side-dress plants with organic fertilizer every two weeks starting when tomatoes are about 1 inch in diameter.


For indeterminate (vining) tomatoes, remove suckers (small shoots that form in the leaf axils) to improve air circulation and promote fruit development. Use soft materials like cloth strips or twine to tie stems to stakes or trellises as the plants grow.

Harvesting and Storing

  • Harvest tomatoes when they are firm and fully colored. Leave them on the vine as long as possible for optimal flavor.

  • Store ripe tomatoes at room temperature, away from direct sunlight. Avoid refrigeration, as it can affect their taste and texture.

  • To preserve tomatoes, freeze them whole after coring, or can them for longer storage.

By following these guidelines for planting and caring for tomatoes, you'll be rewarded with a bountiful harvest of delicious, homegrown tomatoes throughout the season.


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