Plant tomato seedlings deeper than they grew in their containers

Bury tomato seedlings so that only the top two or three sets of leaves show above the soil. This means planting them much deeper than the soil line in their nursery pot — often 6 to 8 inches deeper, depending on the seedling's height. Tomatoes are one of the few plants that will grow roots all along a buried stem, and those extra roots make the plant stronger and more drought-resistant.

The buried stem will develop a root system that spreads wider and reaches deeper into the soil. A stronger root system means the plant can pull more water and nutrients during hot weather or dry spells, and it anchors the plant better against wind. This is especially useful if you live somewhere with inconsistent rainfall or intense summer heat.

Key Takeaways

  • Bury the stem so only the top two or three leaf sets remain above soil, removing lower leaves first.
  • Tomatoes will sprout roots along any buried stem, creating a deeper, wider root system than shallow planting allows.
  • Deeper planting helps plants survive drought and wind better because more roots can draw water and anchor the plant.
  • Plant at an angle if your seedling is tall and leggy, and the buried portion will still develop roots.

Remove lower leaves before burying the stem

Before you plant, strip off all the leaves that will end up below the soil line. Leave only the top two or three sets of leaves on the seedling. Any leaves buried in soil will rot and can introduce disease into the stem.

Use clean scissors or pinch the leaves off by hand, working from the bottom up. This takes only a minute and prevents a common source of fungal problems later. The buried stem itself is fine — it is only the leaves that need to come off.

Dig a hole or trench deep enough for most of the stem

For a typical 6- to 8-inch seedling from a nursery, dig a hole 4 to 6 inches deep. For a taller, leggier seedling (one that grew tall and thin indoors), you have two options: dig a deeper hole, or dig a shallow trench and lay the seedling at an angle so the top of the plant points upward.

If you choose the angled method, bury the stem at roughly a 45-degree angle with the leafy top still pointing up. The buried portion will straighten itself as it grows, and roots will develop all along the angled stem. Either method works — use whichever fits your garden space better.

Space plants and firm the soil around them

Space tomato plants 24 to 36 inches apart, depending on the variety. Determinate types (bush tomatoes) can be closer; indeterminate types (vining tomatoes) need more room. Check your seed packet or plant label for the specific spacing your variety needs.

After you place the seedling in the hole, fill it with soil and press gently but firmly around the stem. The soil should be snug enough that the plant stands upright without wobbling, but not so packed that water cannot drain. Water when ready after planting to settle the soil and remove air pockets.

Water well after planting and in the days after

Water the seedling thoroughly right after planting so the soil makes full contact with the buried stem. For the first week, water every day or every other day if the weather is hot and dry. The goal is to keep the soil consistently moist (not waterlogged) while the new roots are developing.

After the first week, you can move to a normal watering schedule — usually once or twice a week depending on rainfall and heat. Mulch around the base of the plant with 2 to 3 inches of straw or wood chips to help the soil hold moisture and keep the roots cooler.

Hardening off seedlings before planting outdoors

If your seedlings have been growing indoors under lights, they need a week of gradual exposure to outdoor sun and wind before planting. This process is called hardening off. Start by placing seedlings outside in a sheltered, shaded spot for an hour or two, then gradually increase their time outside and sun exposure over 7 to 10 days.

Hardened-off seedlings are tougher and less likely to wilt or get sunburned when planted. If you skip this step, seedlings grown entirely indoors may struggle for the first few weeks outdoors, even if they are planted correctly.

Frequently Asked Questions

Can I plant a tomato seedling at the same depth it was growing in its pot?

You can, but it is not ideal. Shallow planting gives you a smaller root system that is more vulnerable to drought and wind. Deep planting takes only a few extra minutes and gives you a much stronger plant, so it is worth doing if you have the time.

What if my seedling is very tall and spindly?

Tall, thin seedlings are usually the result of growing indoors without enough light. Plant them at an angle or in a deeper hole — the buried stem will develop roots and the plant will straighten as it grows. Pinch off the top growing tip once the plant is established to encourage bushier growth.

Will burying the stem hurt the plant?

No. Tomato stems are designed to root along their length, so burying them is actually beneficial. The only risk is if you bury leaves — those will rot. Remove all leaves below the soil line before planting and you will have no problems.

How long does it take for buried stems to develop roots?

Roots begin forming along the buried stem within a week or two, though you will not see them. By the time the plant is 4 to 6 weeks old, the new root system will be well established and the plant will be noticeably more vigorous than a shallow-planted seedling.