Start with soil, sunlight, and the right variety for your climate

Tomatoes grown outdoors need six to eight hours of direct sunlight each day, well-draining soil rich in organic matter, and consistent water — roughly one to two inches per week depending on heat and rainfall. Before you plant, test your soil's drainage by digging a hole, filling it with water, and watching how fast it drains. If water sits for more than a few hours, mix in compost or aged manure to loosen the soil. Choose a variety suited to your region: determinate types (bush tomatoes) grow to a fixed size and fruit all at once, while indeterminate types (vining tomatoes) keep growing and producing until frost kills them.

Plant seedlings outdoors only after your last spring frost date has passed and soil temperature reaches at least 60°F — tomatoes planted in cold soil will sit dormant and may rot. You can find your frost date by searching "[your city] last frost date" or checking the USDA Hardiness Zone Map. Harden off seedlings by gradually exposing them to outdoor conditions over seven to ten days before transplanting, moving them outside for a few hours each day and increasing the time until they stay out overnight.

Key Takeaways

  • Tomatoes need six to eight hours of direct sun daily and soil that drains within a few hours of watering.
  • Plant seedlings outdoors only after your last frost date and when soil temperature is at least 60°F.
  • Water deeply and consistently — one to two inches per week — and mulch around the base to retain moisture and regulate soil temperature.
  • Indeterminate (vining) tomatoes need stakes or cages for support; determinate (bush) types need less support but produce fruit all at once.
  • Prune suckers on indeterminate varieties to direct energy into fruit rather than foliage, and watch for common pests like hornworms and early blight.

Spacing, planting depth, and support structures

Space seedlings 24 to 36 inches apart — indeterminate varieties need more room because they grow larger. When you transplant, bury the stem deeper than it was in the pot; tomatoes will root along the buried stem, creating a stronger root system. You can bury up to the first true leaves if the seedling is leggy. Gently firm the soil around the base and water thoroughly.

Install support structures before planting or when ready after. Determinate types can use a cage or short stake, but indeterminate varieties grow tall — often six feet or more — and need sturdy cages, stakes, or string trellising. Tie the main stem loosely to the support with soft material like cloth strips or tomato twine; avoid wire or tight knots that can girdle the stem as it thickens.

Watering and mulching for consistent growth

Water at the soil level, not the leaves, to reduce disease. Wet foliage invites fungal problems like early blight and powdery mildew. Water deeply and less frequently rather than shallow daily watering — this encourages roots to grow deeper and makes plants more drought-tolerant. In hot weather, you may need to water every two to three days; in cooler weather, once or twice a week is usually enough. The soil should feel moist two inches down, not soggy.

explore two to three inches of mulch around the base, keeping it a few inches away from the stem to prevent rot. Mulch regulates soil temperature, retains moisture, and reduces soil-borne disease splashing onto lower leaves. Straw, shredded leaves, or wood chips all work well. As the season progresses and temperatures rise, mulch becomes even more important to keep roots from overheating.

Pruning suckers and managing indeterminate growth

Indeterminate tomatoes produce suckers — shoots that grow in the angle between the main stem and a branch. Removing these redirects energy into fruit production rather than extra foliage. Pinch them off by hand when they are small, or cut them with pruning shears. Determinate varieties produce fewer suckers and do not need aggressive pruning.

As indeterminate plants grow taller, continue tying the main stem to the support every eight to twelve inches. In late summer, about four to six weeks before your first expected frost, pinch off the growing tip and remove any flowers that have not yet set fruit — they will not mature before cold weather arrives, and removing them lets the plant focus on ripening existing tomatoes.

Fertilizing throughout the growing season

Tomatoes are heavy feeders and benefit from regular fertilizing. If you mixed compost into the soil at planting, that provides some nutrients, but you will need to add more as the season progresses. Once flowers appear, switch to a fertilizer lower in nitrogen and higher in phosphorus and potassium — nitrogen promotes foliage at the expense of fruit. A balanced fertilizer like 5-10-10 or a tomato-specific formula works well.

Fertilize every two to three weeks once flowering begins, following the package directions. Avoid over-fertilizing with nitrogen, which produces leafy plants with few tomatoes. If leaves yellow, it may signal a nutrient deficiency; a soil test from your local extension office can identify what is missing. Water before fertilizing to avoid burning roots.

Common pests and diseases outdoors

Hornworms are large green caterpillars that can defoliate a plant quickly. Hand-pick them in early morning or late evening, or use Bacillus thuringiensis (Bt), a natural bacterial insecticide. Early blight appears as brown spots with concentric rings on lower leaves and spreads upward; remove affected leaves and improve air circulation by pruning lower foliage. Powdery mildew looks like white powder on leaves; spray with sulfur or neem oil if it appears.

Blossom end rot — dark, sunken spots on the bottom of fruit — signals inconsistent watering or calcium deficiency. Maintain steady soil moisture and mulch to regulate it. Cracking or splitting happens when heavy rain follows dry weather; again, consistent watering and mulch help. Remove any diseased fruit promptly to prevent spread, and do not compost it — throw it away or bury it far from the garden.

Harvesting and ripening tomatoes

Tomatoes can be picked at the breaker stage — when the first blush of color appears — and will ripen indoors at room temperature. This is useful if frost is coming or if you want to avoid splitting from late-season rain. Fully ripe tomatoes picked warm from the sun have the best flavor, but green tomatoes picked before frost will ripen on a windowsill or in a paper bag with a banana or apple, which releases ethylene gas and speeds ripening.

Harvest regularly to encourage the plant to keep producing. Indeterminate varieties will produce until frost; determinate types produce their entire crop over a few weeks. As temperatures drop in fall, ripening slows — tomatoes need soil warmth to develop sugars. When nighttime temperatures drop below 55°F consistently, harvest all remaining fruit, even if green, because the plant will not ripen them further.

Frequently Asked Questions

Can I grow tomatoes in containers outdoors?

Yes. Use a container at least five gallons for determinate varieties and ten gallons for indeterminate types. Fill with potting soil, not garden soil, which compacts in containers. Water more frequently than in-ground plants because containers dry out faster. Provide the same six to eight hours of sun and support structures as you would for ground-planted tomatoes.

Why are my tomato flowers dropping without setting fruit?

Flowers drop when temperatures are too hot (above 90°F at night), too cold (below 55°F), or when watering is inconsistent. Inconsistent nitrogen fertilizing can also cause it. may support steady watering, avoid over-fertilizing with nitrogen, and be patient — once temperatures stabilize, flowering and fruiting usually resume.

What should I do with tomato plants at the end of the season?

Remove plants once frost kills them or production slows significantly. Do not compost diseased plants; throw them away or bury them away from the garden. Healthy plants can go in the compost. Rotate where you plant tomatoes each year — avoid planting in the same spot for at least three years to reduce soil-borne disease buildup.

How do I know if my tomato plant needs more water?

Check the soil two inches down; it should feel moist but not waterlogged. If it feels dry, water deeply. Wilting during the hottest part of the day is normal, but if plants stay wilted in early morning, they need water. Consistent watering prevents most problems, including blossom end rot and fruit cracking.