Plant tomatoes in full sun after the last frost date in your area

Tomatoes need at least six to eight hours of direct sunlight each day to produce fruit and develop flavor. Choose a spot in your garden that gets morning sun — this dries dew and reduces disease. Before you plant, check your local frost date (your county extension office or a straightforward search for "[your county] last frost date" will tell you). Planting before that date risks killing seedlings or transplants in a late freeze.

Prepare the soil by mixing in compost or aged manure to a depth of about eight inches. Tomatoes are heavy feeders and need rich, well-draining soil. If your soil is clay-heavy and stays wet, add compost to improve drainage — tomatoes rot if roots sit in standing water. Test your soil pH if you can; tomatoes prefer slightly acidic soil between 6.0 and 6.8, though they tolerate a wider range.

Key Takeaways

  • Plant tomatoes in full sun after your area's last frost date, in soil enriched with compost or aged manure.
  • Space plants two to three feet apart and bury the stem deeper than it was growing in the pot — roots will form along the buried stem and strengthen the plant.
  • Water deeply and consistently, aiming for one to two inches per week, and water at soil level rather than overhead to prevent fungal disease.
  • Support plants with stakes or cages early, before they grow tall and heavy, and prune suckers (shoots between the main stem and branches) on indeterminate varieties to direct energy to fruit.
  • Harvest tomatoes when they reach full color; they continue to ripen after picking if stored at room temperature.

Space plants correctly and bury the stem deeper than it arrived

Space tomato plants two to three feet apart, depending on the variety. Determinate (bush) types can be closer; indeterminate (vining) types need more room for air circulation. When you transplant, bury the stem deeper than it was growing in the pot — bury it up to the first set of true leaves if the plant is leggy. Roots will form all along the buried stem, creating a stronger root system that reaches deeper into the soil and resists drought better.

If you are starting from seed indoors, sow seeds six to eight weeks before your last frost date. Keep soil warm (around 70°F) and moist until seedlings emerge, usually in five to ten days. Once they sprout, move them to bright light — a south-facing window or grow lights placed a few inches above the seedlings. Thin seedlings so each one has room to grow, or transplant them into individual small pots when they develop their first true leaves (the second set of leaves that appear).

Water deeply and consistently at soil level

Tomatoes need one to two inches of water per week, delivered consistently. Water at the base of the plant, soaking the soil rather than wetting the leaves. Wet foliage invites fungal diseases like early blight and powdery mildew. Water in the morning so any splash dries quickly. In hot weather, you may need to water every two to three days; in cooler weather, once or twice a week may be enough. Stick your finger two inches into the soil — if it feels dry, water.

Inconsistent watering causes problems: too little causes blossom-end rot (a dark, sunken spot on the bottom of the fruit), and too much causes cracks and splits in ripe fruit. Mulch around the base of each plant with two to three inches of straw or shredded leaves to keep soil moisture steady and suppress weeds. Keep mulch a few inches away from the stem to prevent rot.

Support plants with stakes or cages early

Install support structures when you plant or very soon after, before the plant grows tall and heavy. A stake driven into the soil at planting time avoids damaging roots later. Use a soft tie — cloth strips, old t-shirt scraps, or commercial plant ties — to loosely bind the main stem to the stake as it grows. Tie it in a figure-eight pattern so the tie does not cut into the stem. Alternatively, use a sturdy cage placed over the plant at planting time; the plant will grow up through it naturally.

Determinate varieties (bush types) need light support; indeterminate varieties (vining types) grow six feet or taller and need sturdy stakes or large cages. Without support, branches break under the weight of fruit, and fruit touching the ground rots or gets eaten by pests.

Prune suckers on indeterminate varieties to focus energy on fruit

On indeterminate (vining) tomatoes, remove suckers — the small shoots that grow in the angle between the main stem and a branch. Suckers grow into full branches that produce leaves but fewer fruit, and they shade the plant. Pinch them off by hand when they are small, or cut them with pruning shears. On determinate (bush) varieties, pruning is optional and less aggressive; these plants naturally stop growing at a certain height and produce most of their fruit at once.

Stop pruning about four weeks before your first expected frost date. At that point, remove only dead or diseased leaves. The plant needs all its foliage to ripen the fruit already on the vine before cold weather arrives.

Watch for common pests and diseases

Hornworms are large green caterpillars that eat leaves and fruit. Hand-pick them if you see them, or spray with spinosad (an organic insecticide) if the infestation is heavy. Whiteflies and spider mites weaken plants by sucking sap; spray with neem oil or insecticidal soap if you notice yellowing leaves or tiny webs. Early blight appears as brown spots with concentric rings on lower leaves; remove affected leaves and improve air circulation by pruning lower branches.

Powdery mildew looks like a white powder on leaves. Prevent it by watering at soil level, not overhead, and spacing plants so air flows between them. If it appears, spray with sulfur or a fungicide labeled for tomatoes. Blossom-end rot is not a disease but a calcium deficiency caused by inconsistent watering; prevent it by keeping soil moisture steady.

Harvest tomatoes when they reach full color

Pick tomatoes when they are fully colored but still slightly firm. They do not need to be soft to be ripe. Tomatoes continue to ripen after picking if stored at room temperature — this is useful if frost is coming and you need to harvest green fruit. Place green tomatoes in a paper bag with a ripe banana or apple; the ethylene gas they release speeds ripening. Tomatoes stored in the refrigerator stop ripening and lose flavor, so keep them on the counter.

In late summer, once nighttime temperatures drop below 55°F, tomato plants stop setting new fruit. At that point, harvest all remaining fruit — even green ones — because the plant will not ripen them before frost. Bring them indoors to finish ripening, or use them for fried green tomatoes or salsa.

Frequently Asked Questions

Can I grow tomatoes in containers?

Yes. Use a pot at least five gallons for determinate varieties and ten gallons for indeterminate types. Fill it with potting soil (not garden soil), and water more often because containers dry out faster than garden beds. Container tomatoes still need six to eight hours of sun and support as they grow.

What is the difference between determinate and indeterminate tomatoes?

Determinate (bush) tomatoes grow to a fixed height, usually two to three feet, and produce most of their fruit at once — good for canning. Indeterminate (vining) tomatoes grow continuously, reaching six feet or taller, and produce fruit throughout the season until frost — good for fresh eating. Check the seed packet or plant label; it will say which type you have.

Why are my tomato flowers falling off without making fruit?

Flowers drop when temperatures are too hot (above 90°F at night) or too cold (below 55°F at night), when the plant is stressed by drought, or when nitrogen fertilizer is too high. may support consistent watering, provide afternoon shade in extreme heat, and avoid over-fertilizing with nitrogen, which promotes leaves at the expense of flowers.

When should I fertilize tomatoes?

If you mixed compost into the soil at planting, you may not need to fertilize at all. If you do, explore a balanced fertilizer (like 10-10-10) every two to three weeks once flowering begins, or use a tomato-specific fertilizer following the package directions. Too much nitrogen produces leafy plants with few fruit.

Can I save seeds from my tomatoes?

Yes, but only from heirloom or open-pollinated varieties. Seeds from hybrid tomatoes (often labeled F1) will not grow true to type. Scoop seeds and gel into a jar, add a little water, and let them ferment for two to three days to remove the gel coating. Rinse, dry on a paper plate for two weeks, and store in a cool, dry place.