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

The best tomatoes start with three things: at least six to eight hours of direct sunlight each day, soil that drains well and holds nutrients, and timing that avoids frost damage to young plants. Tomatoes are warm-season crops—they will not grow in cold soil and will die if exposed to frost. Your local cooperative extension office publishes the average last frost date for your area; plant outdoors only after that date has passed.

Before planting, work compost or aged manure into the top six to eight inches of soil. Tomatoes are heavy feeders and need organic matter to hold moisture and nutrients. If your soil is clay-heavy or compacted, add compost to loosen it—tomato roots need to push down easily. Test your soil pH if you can; tomatoes prefer slightly acidic soil between 6.0 and 6.8.

Key Takeaways

  • Plant tomatoes after your area's last frost date, in a spot that gets six to eight hours of direct sun each day.
  • Mix compost or aged manure into the soil before planting to improve drainage and add nutrients tomatoes need to produce all season.
  • Bury the stem deeper than it grew in the pot—tomatoes will root along the buried stem and develop a stronger plant.
  • Space plants two to three feet apart so air flows between them, which prevents disease and helps fruit ripen evenly.
  • Water deeply at the soil level once or twice a week rather than daily, and mulch around the base to keep soil moisture steady.

Dig the hole deeper than the root ball and bury part of the stem

When you remove a tomato seedling from its pot, you will see the stem and roots. Unlike most plants, tomatoes benefit from being planted deeper than they grew in the container. Bury the stem so that only the top two or three sets of leaves are above ground. Any part of the stem underground will develop roots, giving the plant a stronger foundation and better access to water and nutrients.

Dig a hole large enough to accommodate the stem at this depth. If the seedling is leggy or tall, you can even plant it at an angle—the buried portion will still root. Gently firm the soil around the plant so it stands upright, but do not pack it so hard that water cannot drain through.

Space plants far enough apart for air to move between them

Tomato disease spreads fastest in humid, crowded conditions. Space determinate (bush) varieties at least two feet apart and indeterminate (vining) varieties at least three feet apart. This spacing allows air to flow around the leaves, which dries them after rain or watering and prevents fungal diseases like early blight and powdery mildew.

If you are planting in rows, orient them so morning sun reaches between the plants. Wet leaves dry faster when the sun hits them early in the day. Crowding plants to save space almost always results in more disease and lower yields, so resist the urge to plant too densely.

Water deeply and infrequently rather than daily

Tomatoes need consistent moisture, but daily shallow watering encourages weak roots and fungal disease. Instead, water deeply once or twice a week, depending on heat and rainfall. A deep watering means the soil is wet to a depth of six to eight inches—the water should reach the root zone, not just dampen the surface.

Water at the soil level, not on the leaves. Wet foliage invites disease. If you use a soaker hose or drip line, you solve both problems at once: water goes directly to the roots, and leaves stay dry. In hot weather, you may need to water twice a week; in cooler weather or after rain, once a week may be enough. Stick your finger two inches into the soil—if it feels dry, water. If it feels moist, wait.

Mulch around the base to regulate soil temperature and moisture

After planting and watering in, spread two to three inches of mulch 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—a major source of disease transmission. Use straw, shredded leaves, or wood chips; avoid fresh grass clippings, which can mat down and trap moisture.

As the mulch breaks down over the season, it adds organic matter to the soil. Refresh it mid-season if it has thinned out. Do not pile mulch against the stem, as that can trap moisture and cause rot.

Support or stake plants early to prevent damage later

Determinate varieties stay compact and may need only a short cage or stake. Indeterminate varieties grow tall and heavy with fruit, and they need sturdy support from the start. Install stakes or cages when you plant, not later—driving a stake through established roots damages them and stresses the plant.

Use stakes at least five to six feet tall for indeterminate varieties, or sturdy cages designed for tomatoes. Tie the stem loosely to the support with soft material like cloth strips or tomato twine, leaving room for the stem to grow thicker. As the plant grows, tie it again every eight to twelve inches of new growth. Proper support keeps fruit off the ground, improves air circulation, and makes harvesting easier.

Fertilize every two to three weeks once flowering begins

Tomatoes need nitrogen early to build leaves and stems, but too much nitrogen late in the season produces leafy plants with few flowers. Once the plant starts flowering, switch to a fertilizer lower in nitrogen and higher in phosphorus and potassium—these nutrients support flowering and fruit development. A balanced fertilizer like 5-10-10 works well at this stage.

Follow the package directions for the amount and frequency. Most home gardeners fertilize every two to three weeks once flowers appear. Avoid over-fertilizing, which can cause blossom-end rot (a dark spot on the bottom of the fruit caused by calcium imbalance) and reduce flavor. Consistent watering and mulching help prevent this problem more than extra fertilizer does.

Frequently Asked Questions

Can I plant tomatoes in a container instead of the ground?

Yes. Use a pot at least five gallons for determinate varieties and ten gallons for indeterminate types. Fill it with potting soil mixed with compost, not garden soil. Container tomatoes dry out faster, so check soil moisture every two to three days and water when the top inch feels dry. Containers warm up faster in spring, so you can plant slightly earlier than in-ground tomatoes.

What is the difference between determinate and indeterminate tomatoes?

Determinate varieties grow to a fixed size, flower all at once, and produce most fruit within a short window—good for canning. Indeterminate varieties grow continuously, flower and fruit all season, and produce until frost. Most home gardeners prefer indeterminate types because they produce fresh tomatoes throughout summer and fall.

Why are my tomato flowers dropping off without making fruit?

Flowers drop when soil is too dry, temperatures drop below 55°F at night, or nitrogen is too high. Water consistently and deeply, wait until nighttime temperatures stay above 55°F before planting, and avoid over-fertilizing with nitrogen. Bees also pollinate tomato flowers, so avoid spraying pesticides during bloom time.

How do I prevent blossom-end rot on the bottom of tomatoes?

Blossom-end rot is caused by inconsistent watering and calcium imbalance in the soil, not by a disease. Water deeply and regularly so soil moisture stays even, and mulch to help retain moisture. If your soil is very acidic, add lime to raise the pH and improve calcium availability. Avoid high-nitrogen fertilizer, which can interfere with calcium uptake.

When should I remove leaves from my tomato plant?

Remove only the lowest leaves once the plant is established and flowering—these are most prone to disease and touching soil. Remove leaves that show spots, yellowing, or mold. Do not strip the plant bare; leaves feed the fruit. Remove leaves only on dry days and disinfect your pruning tool between cuts to avoid spreading disease.