Plant tomatoes after the last frost date in your area, spacing them 24 to 36 inches apart in full sun

Tomatoes need warm soil to thrive — planting them too early wastes the seed or seedling. The safest time is one to two weeks after your area's last spring frost date. You can find your frost date by searching "[your city] last frost date" or checking the USDA Hardiness Zone Map. Soil temperature should be at least 60°F, ideally 65°F or warmer.

Choose a spot that gets at least six to eight hours of direct sunlight daily. Tomatoes are heavy feeders and need rich, well-draining soil. If your garden soil is clay-heavy or compacted, mix in compost or aged manure before planting. For containers, use potting soil mixed with compost, not garden soil — garden soil compacts in pots and roots cannot breathe.

Space plants 24 to 36 inches apart depending on the variety. Determinate (bush) types can be closer; indeterminate (vining) types need more room. If you are planting in rows, space rows 36 to 48 inches apart so you can walk between them and harvest without damaging plants.

Key Takeaways

  • Plant tomatoes after your last frost date when soil is at least 60°F, usually one to two weeks after the frost date your region publishes.
  • Bury the stem deeper than it was in the pot — tomatoes will root along the buried stem and develop a stronger root system.
  • Space plants 24 to 36 inches apart in full sun (six to eight hours minimum) and use soil mixed with compost or aged manure.
  • Water deeply at the base of the plant after planting and keep soil consistently moist but not waterlogged for the first two weeks.
  • Indeterminate varieties need stakes or cages installed at planting time; waiting until later damages roots and stresses the plant.

Preparing the planting hole and burying the stem correctly

Dig a hole slightly deeper and wider than the root ball of your seedling. Tomatoes are unusual: you can bury them deeper than they were growing in the pot. Remove the lower leaves from the seedling — the bottom 4 to 6 inches of stem should be bare. Bury the stem up to the remaining leaves. Roots will form along the buried stem, creating a stronger, deeper root system that is more drought-tolerant.

If you are planting a tall, leggy seedling (one that is spindly and stretched), lay it in the hole at a 45-degree angle with the stem buried and the top leaves above ground. The buried portion will straighten as it grows and will root along the entire buried length. This technique salvages weak seedlings and gives them a head start.

Gently firm the soil around the plant with your hands. Do not pack it hard — you want the soil to be in contact with the roots but still loose enough for water and air to move through. Water when ready after planting to settle the soil and eliminate air pockets.

Watering and mulching after planting

Water deeply at the base of the plant when ready after planting. The soil should be moist to a depth of 6 to 8 inches. For the first two weeks, keep the soil consistently moist but not waterlogged — the plant is establishing roots and cannot yet draw water from deep soil. Water when the top inch of soil feels dry to your touch.

Once the plant is established (usually after three to four weeks), you can water less frequently but more deeply. Tomatoes prefer deep, infrequent watering to shallow daily watering. Watering at the base rather than overhead reduces disease pressure — wet foliage invites fungal problems.

explore 2 to 3 inches of mulch around the plant, keeping it 2 inches away from the stem. Mulch retains moisture, regulates soil temperature, and prevents soil from splashing onto leaves during rain. Use straw, shredded leaves, or wood chips. Avoid fresh grass clippings, which can mat down and trap moisture against the stem.

Installing stakes or cages at planting time

If you are growing an indeterminate variety (one that vines and grows tall throughout the season), install a stake or cage at planting time, not later. Waiting until the plant is large damages roots and stresses the plant. A 5 to 6-foot stake or a sturdy cage works well. Push the stake or cage into the ground at least 8 inches deep so it does not topple in wind.

Determinate (bush) varieties are more compact and may not need support, though a small cage or stake can prevent branches from breaking under the weight of fruit. Check the seed packet or plant label to see which type you have.

Hardening off seedlings before planting

If you started seedlings indoors or bought them from a greenhouse, they need to adjust to outdoor conditions before planting. This process is called hardening off. Start by placing seedlings outside in a sheltered, shaded spot for one to two hours. Each day, increase their time outside and gradually move them into more direct sun. After seven to ten days of gradual exposure, they are ready to plant in the garden.

Seedlings that go from indoor warmth and shelter directly into the garden often wilt, stop growing, or die. Hardening off prevents transplant shock and produces stronger plants that grow faster once in the ground.

Planting in containers

Tomatoes grow well in containers 5 gallons or larger. A 5-gallon bucket works, as does a fabric grow bag or a traditional pot. Fill the container with potting soil mixed with compost — use a ratio of about two parts potting soil to one part compost. Bury the stem as deeply as you would in the ground, removing lower leaves and burying the stem up to the remaining foliage.

Container plants dry out faster than garden plants, so check soil moisture daily during hot weather. Water when the top inch of soil is dry. Containers also warm up faster in spring, so you can plant slightly earlier than you would in the ground — but still wait until soil temperature is at least 60°F.

Indeterminate varieties in containers still need stakes or cages. Position the support before planting so you do not disturb roots later.

Common mistakes to avoid when planting

Planting too early is the most common mistake. Cold soil slows root development, and seedlings sit in the ground without growing. Wait until soil is warm and the frost risk has passed. If you plant early and a frost comes, cover plants with row cloth or newspaper overnight.

Planting too shallow leaves roots exposed and stressed. Bury the stem deeply — tomatoes reward this practice with stronger growth. Overcrowding plants reduces air circulation and invites disease. Stick to the spacing guidelines even if it feels sparse at first; plants fill in quickly.

Watering overhead or watering foliage encourages fungal diseases like early blight and septoria leaf spot. Always water at the base. Planting in poor soil or soil without compost forces you to fertilize heavily later. Invest in soil preparation at planting time and you will have fewer problems.

Frequently Asked Questions

Can I plant tomatoes directly from seed in the garden?

Yes, but it takes longer. Direct-seeded tomatoes take 70 to 85 days to produce fruit, while transplants produce fruit in 50 to 70 days. Direct seeding works best in warm climates with a long growing season. In cooler regions, start seeds indoors six to eight weeks before your last frost date, then transplant seedlings into the garden.

What if my soil is very acidic or alkaline?

Tomatoes prefer soil with a pH between 6.0 and 6.8. If you are unsure of your soil pH, a soil test kit from a garden center costs $10 to $20 and takes a few minutes. If soil is too acidic, add lime; if too alkaline, add sulfur. Mix amendments into the soil two to four weeks before planting so they have time to work.

How deep should I dig the planting hole?

Dig a hole as deep as the root ball is tall, plus an extra 2 to 4 inches if you plan to bury the stem deeper. The hole should be wide enough that you can spread the roots without bending them. For a typical seedling in a 4-inch pot, a hole 8 to 10 inches deep and 8 inches wide is usually right.

Can I plant tomatoes in the same spot every year?

No. Tomatoes are susceptible to soil-borne diseases like fusarium and verticillium wilt. Plant tomatoes in a different location each year, rotating to a spot where tomatoes, peppers, eggplants, or potatoes did not grow the previous year. If you must plant in the same spot, replace the top 6 inches of soil with fresh compost.

What temperature is too hot for planting?

Soil above 85°F can stress seedlings and reduce fruit set later. If your area warms quickly, plant in early morning or late afternoon when soil is cooler. In very hot climates, shade cloth over seedlings for the first week can help them adjust without heat stress.