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

Tomatoes need at least six to eight hours of direct sunlight each day, well-draining soil rich in organic matter, and consistent watering. Before you plant, test your soil pH — tomatoes prefer 6.0 to 6.8. If your soil is too acidic or alkaline, amend it with lime or sulfur several weeks before planting. Choose a spot where water drains away after rain rather than pooling, because soggy soil invites disease.

Pick a variety suited to your region. Determinate types (bush tomatoes) grow to a fixed size and produce most fruit at once, making them good for canning. Indeterminate types (vining tomatoes) grow continuously and produce fruit all season, which works better if you want fresh tomatoes through summer and fall. Check your local growing season length — if you have fewer than 70 frost-free days, start seeds indoors eight weeks before your last spring frost, or buy transplants from a nursery.

Plant transplants deeper than they came in their pot. Bury the stem up to the first true leaves; tomatoes will root along the buried stem and develop a stronger base. Space plants 24 to 36 inches apart so air can move between them and reduce disease pressure.

Key Takeaways

  • Tomatoes need six to eight hours of direct sun daily and soil that drains well, with a pH between 6.0 and 6.8.
  • Determinate varieties produce most fruit at once and suit canning; indeterminate varieties produce all season and work better for fresh eating.
  • Bury transplant stems deep — up to the first leaves — to encourage a stronger root system.
  • Water at the soil level early in the morning, aiming for one to two inches per week, and mulch to keep soil moisture steady.
  • Prune suckers on indeterminate varieties and stake or cage plants early to prevent damage as they grow.

Water consistently at soil level, not from above

Tomatoes need steady moisture — about one to two inches of water per week, including rain. Water early in the morning at the base of the plant, not on the leaves. Wet foliage invites fungal diseases like early blight and late blight, which spread quickly in humid conditions. A soaker hose or drip line delivers water directly to the roots and keeps leaves dry.

Mulch around each plant with two to three inches of straw or shredded leaves, leaving a gap around the stem. Mulch keeps soil temperature even, reduces water loss, and prevents soil from splashing onto leaves during rain or watering. In hot climates, mulch also keeps roots cooler.

If you miss a watering and the soil dries out, do not overcompensate by flooding the plant. Irregular watering causes problems like blossom-end rot (a dark, sunken spot on the fruit) and fruit cracking. Aim for steady moisture rather than feast-or-famine cycles.

Support plants with stakes, cages, or strings as they grow

Indeterminate tomatoes can reach six feet or taller and will collapse under their own weight without support. Install stakes or cages early, right after planting, so you do not damage roots later. A sturdy cage should be at least five feet tall; flimsy cages sold at garden centers often topple in wind or under a heavy crop.

Alternatively, use a stake and tie the main stem loosely with soft twine or cloth strips as the plant grows. Tie in a figure-eight pattern — one loop around the stake, one around the stem — so the stem can move slightly without rubbing raw against the stake.

Determinate bush varieties need less support but still benefit from a cage or short stake to keep fruit off the ground and improve air circulation.

Prune suckers on indeterminate varieties to direct energy to fruit

Indeterminate tomatoes grow suckers — shoots that sprout in the angle between the main stem and a branch. Removing these suckers channels the plant's energy into producing larger fruit rather than extra foliage. Determinate varieties produce fewer suckers and do not need aggressive pruning.

Pinch off suckers when they are small, before they woody and hard to remove. On an indeterminate plant, keep the main stem and allow one or two side branches to develop; remove everything else. Stop pruning about four weeks before your first expected frost so the plant can focus on ripening the fruit already on it.

Do not remove leaves to expose fruit to more sun — the leaves protect fruit from sunscald, a white or yellow patch that appears where sun hits exposed skin directly.

Fertilize every two to three weeks once flowers appear

Tomatoes are heavy feeders. Work a balanced fertilizer (such as 5-10-10 or 10-10-10) into the soil before planting. Once the plant flowers, side-dress with fertilizer or explore a liquid fertilizer every two to three weeks. Avoid high-nitrogen fertilizers, which produce lots of leaves but few flowers and fruit.

If leaves turn yellow or growth slows, the plant may need magnesium or calcium. Dissolve one tablespoon of Epsom salt in a gallon of water and pour it around the base of the plant. Calcium deficiency causes blossom-end rot; adding crushed eggshells or gypsum to the soil before planting helps prevent it.

Stop fertilizing about four weeks before the first frost. Late fertilizing pushes new growth that will not have time to ripen before cold weather arrives.

Watch for common pests and diseases, and act early

Early blight appears as brown spots with concentric rings on lower leaves, usually in mid-summer when humidity is high. Remove affected leaves and improve air circulation by pruning lower branches. Late blight causes gray-green water-soaked spots on leaves and fruit; it spreads fast in cool, wet weather. Remove infected plants entirely if late blight appears.

Hornworms are large green caterpillars that eat leaves and fruit. Hand-pick them or spray with spinosad, an organic insecticide. Whiteflies cluster on the undersides of leaves and weaken the plant; spray with insecticidal soap or neem oil. Septoria leaf spot causes small circular spots with dark borders; remove affected leaves and do not water from above.

The best defense is prevention: choose disease-resistant varieties when available (look for letters like VF or EB on the label), space plants for good air flow, water at soil level, and remove lower leaves as the plant grows. Stake or cage plants early so fruit does not touch the ground.

Harvest when fruit is fully colored but still slightly firm

Pick tomatoes when they are fully colored but still have a slight give when squeezed gently. Fruit picked at this stage ripens off the vine and develops better flavor than fruit picked rock-hard. If frost is coming and you have green tomatoes still on the plant, pick them and place them in a paper bag with a ripe banana or apple; the ethylene gas they release speeds ripening indoors.

Tomatoes stored at room temperature taste better than those refrigerated, but cold slows ripening. If you must refrigerate, bring them back to room temperature before eating to restore flavor.

Indeterminate plants keep producing until frost kills them. In most regions, you can harvest fruit from June or July through September or October, depending on your climate.

Frequently Asked Questions

Why are my tomato flowers dropping 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 inconsistent watering, or when nitrogen fertilizer is too high. Keep soil moisture steady, avoid over-fertilizing with nitrogen, and be patient — once temperatures moderate, flowering and fruit set usually resume.

What causes yellow leaves on my tomato plant?

Yellow leaves can mean nitrogen deficiency, overwatering, early blight, or natural aging of lower leaves. If yellowing starts at the bottom and moves up, remove those leaves to improve air flow. If it spreads rapidly or appears with brown spots, it is likely early blight — remove affected leaves and improve air circulation.

Can I grow tomatoes in containers?

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

How do I save seeds from my tomatoes?

Scoop seeds and gel from a ripe tomato into a jar, add a little water, and let it ferment for two to three days. Rinse the seeds thoroughly, spread them on a paper towel to dry completely, and store in a cool, dry place. Seeds from hybrid varieties will not grow true to type; save seeds only from heirloom or open-pollinated varieties.

When should I stop watering before harvest?

Do not stop watering — keep soil consistently moist right up to frost. Stopping water late in the season stresses the plant and can cause fruit cracking or blossom-end rot. Water normally until cold weather kills the plant.