Plant tomatoes after the last frost date in your area, burying the stem deeper than it grew in the pot

Tomatoes need warm soil to thrive—planting them before the last frost will stunt or kill them. Check your local frost date by searching "[your city] last frost date" or asking at a garden center; it typically falls between mid-April and late May depending on where you live. Soil temperature should be at least 60°F, ideally 65°F or warmer.

When you plant, bury the stem deeper than it currently sits in its pot. Tomatoes will grow roots all along the buried stem, creating a stronger root system. You can bury up to the first set of true leaves—remove any leaves that would sit below the soil line, since buried leaves can rot.

Key Takeaways

  • Wait until after your area's last frost date and soil reaches 60°F or warmer before planting outdoors.
  • Space plants 24 to 36 inches apart depending on variety, with determinate types closer together and indeterminate types farther apart.
  • Bury the stem deeper than it grew in the pot to encourage a stronger root system.
  • Water deeply at the base after planting and keep soil consistently moist but not waterlogged for the first two weeks.
  • Add a cage or stake at planting time rather than later, when roots are already established.

Spacing: How far apart to plant tomato varieties

Determinate (bush) tomatoes, which grow to a fixed size and produce most fruit at once, can be spaced 24 inches apart. Indeterminate (vining) tomatoes, which grow continuously and produce fruit all season, need 36 inches between plants so air can circulate and prevent disease.

If you are unsure which type you have, check the seed packet or plant label—it will say "determinate" or "indeterminate," or use the shorthand "det" or "indet." Spacing matters because crowded plants trap moisture on leaves, inviting fungal disease. Wider spacing also makes pruning and harvesting easier later.

Digging the hole and preparing the soil

Dig a hole slightly wider and deeper than the root ball of your seedling. If your soil is poor or heavy clay, mix in 2 to 3 inches of compost or aged manure into the hole and surrounding area—tomatoes are heavy feeders and benefit from organic matter that holds moisture and nutrients.

If you are planting in a container, use potting soil, not garden soil. A 5-gallon bucket or larger works for determinate varieties; indeterminate types do better in 10-gallon containers or larger. Containers dry out faster than ground soil, so you will water more often.

Burying the stem and setting support structures

Remove the seedling from its pot and gently loosen the root ball with your fingers. Set it in the hole so the lowest leaves sit just above soil level, then backfill and firm the soil gently. Water when ready to settle the soil and eliminate air pockets.

Install a cage or stake at planting time, not weeks later. Pushing a stake through established roots damages them and stresses the plant. A cage should be sturdy enough to support the plant when it is heavy with fruit—flimsy cages often collapse mid-season. For indeterminate varieties, a tall stake (5 to 6 feet) or a sturdy cage works; for determinate types, a shorter cage (4 to 5 feet) is usually enough.

Watering after planting

Water deeply at the base of the plant right after planting, soaking the soil to 6 to 8 inches deep. For the first two weeks, keep soil consistently moist but not waterlogged—squeeze a handful; it should feel like a wrung-out sponge. Overwatering early on can cause root rot, while underwatering stresses the plant and invites pests.

Once the plant is established (after about three weeks), water less frequently but more deeply. Tomatoes prefer deep, infrequent watering to shallow daily watering, which encourages shallow roots and makes plants thirsty during dry spells. In hot weather, mature plants typically need 1 to 2 inches of water per week, either from rain or irrigation.

Hardening off seedlings before planting

If you grew seedlings indoors under lights, they need to adjust to outdoor sun and wind before planting. This process, called hardening off, takes 7 to 10 days. Start by placing seedlings in a sheltered, shaded spot outdoors for 2 to 3 hours, then gradually increase sun exposure and time outdoors each day.

By the end of the hardening-off period, seedlings should spend a full day and night outside. Skipping this step often results in sunburned leaves (pale patches that turn papery) and stunted growth. If you buy seedlings from a garden center, ask whether they have already been hardened off—many have, and you can plant them directly.

Protecting young plants from pests and weather

Young tomato plants attract cutworms, which sever seedlings at soil level. A straightforward barrier—a toilet paper tube or small paper cup with the bottom removed, pushed 1 inch into the soil around the stem—prevents cutworms from reaching the plant. Leave the barrier in place for 3 to 4 weeks, then remove it.

If frost threatens after planting, cover plants with a frost cloth, old sheet, or row cover in the evening and remove it the next morning when temperatures rise. A single frost can kill young plants, so monitor the forecast for the first few weeks. Once plants are 12 inches tall and established, they are much more cold-tolerant.

Frequently Asked Questions

Can I plant tomatoes in the same spot every year?

No. Tomatoes are susceptible to soil-borne diseases like early blight and fusarium wilt that build up in soil over time. Rotate tomatoes to a different bed each year, or at minimum wait three years before planting tomatoes in the same spot. If you must replant in the same location, replace the top 6 inches of soil.

What if my seedlings are tall and leggy?

Leggy seedlings (tall and thin) happened indoors because they did not get enough light. Plant them deeper than usual—you can bury up to the first true leaves, and the buried stem will root and create a sturdier plant. Leggy seedlings will catch up once they are in the ground with full sun.

How deep should I water after planting?

Water until soil is moist 6 to 8 inches deep. Stick your finger into the soil after watering; you should feel moisture at that depth. Shallow watering encourages shallow roots and makes plants vulnerable to drought. Deep watering once or twice a week is better than light daily watering.

Do I need to fertilize at planting time?

If you mixed compost or aged manure into the planting hole, you have added nutrients and do not need fertilizer yet. If your soil is poor, a balanced fertilizer (like 10-10-10) mixed into the hole at planting helps. Avoid high-nitrogen fertilizers, which promote leafy growth at the expense of fruit.

What if I plant too early and frost comes?

Cover plants with a frost cloth, blanket, or row cover before sunset and remove it after sunrise. Water the soil before covering—moist soil holds heat better than dry soil. If plants are already damaged by frost (blackened leaves), they may recover if the damage is light, but severe frost damage usually kills young plants.