Plant tomatoes in spring after the last frost, spacing them 24 to 36 inches apart in soil that drains well and gets at least 6 to 8 hours of direct sun each day

Tomatoes need warm soil to thrive — planting too early is the most common mistake home gardeners make. Wait until nighttime temperatures stay above 50°F and the soil has warmed to at least 60°F, which usually means late April or May depending on where you live. You can check your local frost date by searching "[your city] last frost date" online, or ask at a local garden center.

The soil itself matters as much as timing. Tomatoes grow best in soil that holds moisture but does not stay soggy. If your garden soil is heavy clay, mix in 2 to 3 inches of compost or aged manure before planting. If it is sandy and drains too fast, add compost to help it retain water. The goal is soil that feels crumbly and dark, not hard or pale.

Key Takeaways

  • Plant tomatoes after your last frost date when soil temperature reaches 60°F, usually in late spring.
  • Space plants 24 to 36 inches apart in a location that receives 6 to 8 hours of direct sunlight daily.
  • Dig a hole deeper than the root ball and bury the stem up to the first true leaves, which helps the plant develop a stronger root system.
  • Water deeply at the soil level once or twice weekly rather than daily, and avoid wetting the leaves to prevent disease.
  • Install a cage or stake at planting time so you do not damage roots later when the plant is larger.

Choosing the right location and preparing the soil

Tomatoes are sun-hungry plants. They need at least 6 to 8 hours of direct sunlight — more is better. If your garden gets only 4 to 5 hours of sun, you will get fewer tomatoes and they will ripen more slowly. Walk your garden at different times of day to see where shadows fall, and pick the sunniest spot available.

Before you dig, test your soil if you can. A straightforward soil test kit from a garden center costs $10 to $15 and tells you whether your soil is acidic, neutral, or alkaline. Tomatoes prefer soil that is slightly acidic to neutral (a pH between 6.0 and 6.8). If your soil is very acidic, add lime. If it is too alkaline, add sulfur. These amendments work slowly, so add them a few weeks before planting if possible.

Work the compost or aged manure into the top 8 to 10 inches of soil with a garden fork or tiller. Do not use fresh manure — it can burn plant roots and introduce disease. If you are planting in the same spot where tomatoes grew last year, add extra compost because tomatoes are heavy feeders and deplete soil nutrients quickly.

Digging the hole and planting the seedling

Dig a hole that is slightly deeper and wider than the root ball of your seedling. Here is the key difference between tomatoes and most other plants: bury the stem deeper than it was growing in the pot. Remove the lower leaves and bury the stem up to the first set of true leaves (the leaves that look like actual tomato leaves, not the small rounded seed leaves). Roots will form all along the buried stem, creating a stronger root system that can support a larger plant and reach deeper water during dry spells.

Gently remove the seedling from its pot and loosen the roots with your fingers. If the roots are tightly wound in a circle, make three or four vertical cuts along the root ball to encourage them to spread outward into the soil. Place the seedling in the hole, backfill with soil, and press gently but firmly so there are no air pockets. Water when ready after planting to settle the soil.

If you are planting a very tall or leggy seedling, you can lay it in a shallow trench at a 45-degree angle with the top of the plant pointing upward. The buried portion of the stem will root, and the plant will straighten as it grows toward the sun.

Installing support and spacing plants correctly

Install a cage or stake at planting time, not later. Pushing a support into the soil after the plant is established damages roots and stresses the plant. Determinate varieties (bush types that grow to a fixed size) usually need a cage or short stake. Indeterminate varieties (vining types that grow all season) need a tall stake, string trellis, or sturdy cage at least 5 to 6 feet tall.

Space plants 24 to 36 inches apart depending on the variety. Determinate types can be closer (24 inches), while indeterminate types need more room (30 to 36 inches) because they grow larger and need air circulation to prevent disease. If you are planting in rows, space rows 36 to 48 inches apart so you can walk between them and harvest easily.

Watering and mulching after planting

Water deeply at the soil level once or twice per week, depending on rainfall and heat. A deep watering once a week is better than shallow watering every day — it encourages roots to grow deeper and makes the plant more drought-tolerant. In very hot weather or sandy soil, you may need to water twice weekly. The soil should feel moist 2 to 3 inches down, not soggy.

Water at the base of the plant and avoid wetting the leaves. Wet foliage invites fungal diseases like early blight and powdery mildew. If you must water overhead, do it early in the morning so leaves dry quickly.

After planting, spread 2 to 3 inches of mulch (shredded bark, straw, or compost) 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 also reduces disease.

Common mistakes to avoid when planting

Planting too early is the biggest mistake. Cold soil slows growth and can cause the plant to sit dormant for weeks. If you plant in April and soil is still 50°F, the seedling will not grow much until soil warms in May. You lose nothing by waiting two weeks for warmer soil.

Overcrowding is the second mistake. Tomatoes planted too close together compete for water and nutrients, and poor air circulation leads to disease. Stick to the spacing guidelines even if it means fewer plants in your garden — you will get more fruit from well-spaced plants.

Planting in shade or part shade is common in small gardens, but it results in slow growth, fewer flowers, and delayed ripening. If your garden is shaded, consider growing tomatoes in containers on a sunny patio or deck instead.

Burying the plant at the same depth it was growing in the pot is a missed opportunity. Bury it deeper to build a stronger root system. The only exception is if the seedling is already very tall and leggy — in that case, the deeper planting is even more important.

Planting tomatoes in containers

If you do not have garden space or your soil is poor, tomatoes grow well in containers. Use a pot at least 5 gallons for determinate varieties and 10 gallons for indeterminate types. Fill it with potting mix (not garden soil), not plain compost. Potting mix drains better and does not compact over time.

Plant the seedling using the same deep-planting method as in the garden. Place the container in the sunniest spot available — at least 6 to 8 hours of direct sun. Container plants dry out faster than garden plants, so check soil moisture every day or two. Water when the top inch of soil feels dry. In hot weather, you may need to water daily.

Container tomatoes also need more frequent feeding because water drains through the pot and carries nutrients away. Feed every two weeks with a balanced fertilizer (like 10-10-10) or a tomato-specific fertilizer once the plant starts flowering.

Frequently Asked Questions

Can I plant tomatoes in the same spot every year?

You can, but it is not ideal. Tomatoes are susceptible to soil-borne diseases like fusarium wilt and early blight that build up in soil over time. If you must plant in the same spot, add extra compost, remove all plant debris from the previous year, and rotate to a different crop (like beans or lettuce) for at least one year before planting tomatoes again.

What if my seedlings are very tall and spindly?

Tall, thin seedlings happen when plants do not get enough light indoors. Plant them deeper than usual — you can bury them up to the first true leaves or even lay them in a trench at an angle. The buried stem will root and the plant will develop a stronger base. Once in the garden with full sun, new growth will be stockier.

How long after planting will I see flowers and fruit?

Most tomato varieties flower 4 to 6 weeks after planting and produce ripe fruit 60 to 85 days after planting, depending on the variety. Check the seed packet or plant label for the specific days-to-maturity number. Cooler weather and less sun slow this timeline.

Do I need to fertilize at planting time?

If you mixed compost or aged manure into the soil before planting, you do not need to fertilize when ready. Once the plant starts flowering (usually 4 to 6 weeks after planting), begin feeding every two weeks with a balanced or tomato-specific fertilizer. Too much nitrogen early on produces lots of leaves but few flowers.

What is the difference between determinate and indeterminate tomatoes?

Determinate varieties grow to a fixed size (usually 3 to 4 feet), produce most of their fruit at once, and stop growing. They are good for canning and small spaces. Indeterminate varieties grow all season (sometimes 6 to 8 feet or taller), produce fruit continuously until frost, and need tall support. Choose based on your space and whether you want one big harvest or fruit all summer.