Plant tomatoes in full sun, in soil rich with compost, after the last frost date in your area

Tomatoes need at least six to eight hours of direct sunlight each day to grow well and produce fruit. Before you dig, check your local frost date — the date when freezing temperatures typically stop for the season. Plant tomatoes only after that date has passed, because frost will kill seedlings and young plants. You can find your frost date by searching "[your city] last frost date" or by contacting your local cooperative extension office.

The soil matters as much as the timing. Mix compost or aged manure into the top six to eight inches of soil before planting. Tomatoes are heavy feeders and need nutrient-rich ground to thrive. If your soil is clay-heavy or compacted, add compost to loosen it and improve drainage — tomatoes rot if water pools around the roots.

Space plants 24 to 36 inches apart, depending on the variety. Determinate varieties (bush types that stop growing at a set height) can be closer; indeterminate varieties (vining types that grow all season) need more room for air circulation. Crowded plants trap moisture and invite disease.

Key Takeaways

  • Plant after your local last frost date in soil mixed with compost, in a spot that gets six to eight hours of direct sun daily.
  • Space plants 24 to 36 inches apart to allow air to move around the leaves and reduce disease.
  • Bury the stem deeper than it was in the pot — tomatoes will root along the buried stem and develop a stronger root system.
  • Water deeply at the soil level once or twice a week rather than daily, and mulch around the base to keep moisture steady and prevent soil-borne disease from splashing onto leaves.

Dig the hole and bury the stem deeper than it came in the pot

When you remove a tomato seedling from its pot, the stem is usually only a few inches tall. Bury it deeper — up to the lowest set of true leaves. Tomatoes will grow roots all along the buried stem, creating a stronger, deeper root system that reaches water and nutrients better than a shallow root system would.

Dig a hole wide enough that the roots spread out without bending or circling. If the seedling is leggy (tall and thin with few leaves), lay it in the hole at an angle so the buried portion of the stem is still underground. The plant will straighten as it grows.

Pat the soil firmly around the base so there are no air pockets, but do not compact it so hard that water cannot drain. The soil should hold the plant upright without being rock-solid.

Water deeply and mulch to keep moisture steady

Water tomatoes at the soil level, not on the leaves. Wet foliage invites fungal disease like early blight and powdery mildew. Water deeply once or twice a week rather than a little bit every day. Deep watering encourages roots to grow down into the soil; shallow daily watering keeps roots near the surface where they dry out faster.

Lay two to three inches of mulch — straw, shredded leaves, or wood chips — around the base of each plant, keeping it a few inches away from the stem. Mulch keeps soil temperature steady, reduces water loss, and prevents soil from splashing onto leaves during rain or watering, which spreads soil-borne diseases.

The amount of water a tomato needs depends on rainfall, temperature, and soil type. In hot, dry weather, you may need to water twice a week. In cool weather with regular rain, once a week or less may be enough. Stick your finger two inches into the soil; if it feels dry, water. If it feels moist, wait.

Support or stake the plant as it grows

Determinate bush varieties usually need little support, but indeterminate vining varieties must be staked or caged to keep fruit off the ground and improve air circulation. Install stakes or cages at planting time rather than later, when you risk damaging roots.

Use a stake at least five to six feet tall for indeterminate varieties, or a sturdy cage. Tie the main stem loosely to the stake with soft ties — old cloth strips, garden twine, or commercial plant ties work well. Tie in a figure-eight pattern so the tie does not cut into the stem as it thickens. Retie every two to three weeks as the plant grows.

Cages work well for determinate varieties and smaller indeterminate plants, but they need to be sturdy enough to support a plant heavy with fruit. Flimsy cages collapse under the weight.

Fertilize every two to three weeks once flowering begins

Tomatoes planted in compost-rich soil have enough nutrients to start, but they need feeding once they begin to flower and set fruit. Use a balanced fertilizer — something like 5-10-10 or 10-10-10 — or a fertilizer formulated for tomatoes. Follow the package directions for how much to use and how often.

Overfertilizing, especially with nitrogen, produces lots of leaves but few flowers and fruit. Stick to the schedule on the package rather than feeding more often or in larger amounts.

Side-dress with compost every three to four weeks as an alternative to liquid fertilizer. Spread an inch of compost around the base of each plant, keeping it a few inches from the stem, and water it in.

Watch for common problems and catch them early

Early blight appears as brown spots with concentric rings on lower leaves, usually starting four to six weeks after planting. Remove affected leaves as soon as you see them, and do not compost them — throw them away. Water at the soil level only, and improve air circulation by pruning lower branches.

Blossom end rot shows up as a dark, sunken spot on the bottom of the fruit. It is caused by uneven watering, not disease. Keep soil moisture steady by watering deeply and mulching, and the problem usually stops on new fruit.

Hornworms are large green caterpillars that can strip a plant bare. Hand-pick them if you see them, or spray with spinosad (an organic insecticide) if the infestation is heavy. Check the undersides of leaves where they hide.

Frequently Asked Questions

Can I plant tomatoes in containers?

Yes. Use a pot at least 18 to 24 inches deep and wide, with drainage holes. Fill it with potting mix (not garden soil), and follow the same planting and watering rules. Container tomatoes dry out faster than in-ground plants, so check soil moisture more often and water when the top inch feels dry.

What is the difference between determinate and indeterminate tomatoes?

Determinate varieties grow to a set height (usually 3 to 4 feet), flower all at once, and produce most of their fruit in a short window. Indeterminate varieties grow all season, flower continuously, and produce fruit until frost. Determinate types are good for canning; indeterminate types produce longer for fresh eating.

Should I prune tomato plants?

Indeterminate varieties benefit from pruning suckers (shoots that grow between the main stem and branches) to focus energy on fruit production and improve air circulation. Determinate varieties do not need pruning. Remove lower leaves on any variety once the plant is established to reduce disease pressure.

How long does it take from planting to first fruit?

Most tomato varieties produce ripe fruit 60 to 85 days after planting, though some early varieties are faster and some large slicing types take longer. The timeline depends on variety, temperature, and sunlight. Warmer weather speeds up growth; cool weather slows it.

Can I plant tomatoes in the same spot every year?

No. Tomatoes and related plants (peppers, eggplants, potatoes) should not grow in the same soil for more than two years in a row, because soil-borne diseases build up. Rotate tomatoes to a different bed each year, or replace the top foot of soil if you must plant in the same spot.