Growing Tomatoes

You grow tomatoes by starting seeds indoors six to eight weeks before the last frost, transplanting them deep after the frost passes, giving six to eight hours of sun, watering deeply and evenly, feeding through the season, and supporting the plants until harvest. Most varieties ripen 55 to 90 days after transplanting.

What temperature do tomatoes need to grow?

Tomatoes grow best between 70°F and 75°F (21–24°C) during the day. Fruit set drops below 55°F (13°C) and above 90°F (32°C). Night temperatures near 60°F (16°C) give the strongest flowering.

Cold nights slow growth and cause poor fruit set. Extreme heat makes flowers drop and fades fruit color. Plant after night temperatures stay above 50°F (10°C).

What soil is best for tomatoes?

Tomatoes need deep, well-drained soil with a pH of 6.0 to 6.8. A sandy loam enriched with compost holds moisture yet drains fast, which prevents root rot. Mix two to three inches of compost into the bed before planting.

How do you plant tomatoes?

• Start seeds indoors six to eight weeks before your last frost date.
• Harden off seedlings outdoors for one to two weeks before transplanting.
• Transplant after the last frost, once soil reaches 60°F (16°C).
• Plant seedlings deep, burying two-thirds of the stem, so roots form along it.
• Space plants 18 to 24 inches (45–60 cm) apart, in rows 30 to 36 inches apart.

How often should you water tomato plants?

Tomatoes need about one to two inches of water a week, applied deeply two to three times. Water the soil, not the leaves, to limit disease. A two-inch mulch layer of straw or shredded leaves keeps moisture steady and prevents cracking and blossom end rot.

How do you feed tomatoes?

Feed tomatoes with compost at planting, then a balanced fertilizer as they grow. Switch to a higher-potassium feed once flowers appear, which supports fruit over foliage. Too much nitrogen gives large leafy plants with little fruit.

Do tomato plants need support?

Indeterminate tomatoes need support because they keep growing all season. Stakes, cages, or a string trellis hold fruit off the soil, improve airflow, and cut disease. Determinate (bush) types need only a small cage or none.

Should you prune tomato plants?

Prune indeterminate tomatoes by pinching side shoots (suckers) for larger fruit and better airflow. Leave determinate tomatoes unpruned, because pruning them lowers the harvest. Remove the lowest leaves that touch the soil to slow disease.

How do you manage tomato pests and diseases safely?

Manage tomato pests and diseases with prevention first, then targeted, low-risk controls. Rotate crops each year, choose disease-resistant varieties, keep the bed weed-free, and remove infected leaves early. Reach for chemical pesticides only as a last resort, and follow the label for home garden use.

Common tomato pests

• Tomato hornworm: a large green caterpillar that strips leaves. Hand-pick it, or spray Bt (Bacillus thuringiensis).
• Whiteflies and aphids: tiny sap-feeders that spread virus. Spray insecticidal soap or neem oil, and hang yellow sticky traps.
• Fruitworms: caterpillars that bore into fruit. Remove damaged fruit and use Bt sprays early.

Common tomato diseases

• Early and late blight: brown leaf and fruit spots. Space plants for airflow, water at the base, and remove infected parts.
• Blossom end rot: a dark sunken base from uneven watering and low calcium. Water evenly and keep soil pH near 6.5.
• Leaf curl virus: spread by whiteflies. Control whiteflies and pull badly infected plants.

Choose varieties labeled V, F, and N for built-in resistance to verticillium wilt, fusarium wilt, and nematodes.

When do you harvest tomatoes?

Harvest tomatoes 55 to 90 days after transplanting, depending on variety. Pick fruit at the “breaker” stage, when color first shows, and ripen it indoors at room temperature. Vine-ripened fruit tastes best but cracks and attracts pests if left too long.