Plant tomatoes after your last frost date, in a spot that gets at least six to eight hours of direct sun each day
Tomatoes need warmth to grow. Planting them too early—before the soil has warmed and frost danger has passed—will stunt them or kill them. Check your local frost date (your county extension office or a straightforward search for "last frost date [your city]" will give you the exact date). Wait until at least one to two weeks after that date before putting seedlings in the ground.
The second requirement is sunlight. Tomatoes grown in shade produce fewer fruits and are more prone to disease. Pick a spot in your yard that receives direct sun from mid-morning through afternoon. If you're using containers, you can move them to follow the sun, which is one advantage of container growing.
Soil temperature matters as much as air temperature. Soil should be at least 60°F, ideally 65°F or warmer. If you're planting early in the season and the soil is still cold, wait a week or two. Cold soil will cause the roots to sit dormant and the plant to struggle.
Key Takeaways
- Plant tomato seedlings after your last frost date, when soil temperature reaches at least 60°F, in a location with six to eight hours of direct sun daily.
- Bury the stem deeper than it was growing in the pot—tomatoes will develop roots all along the buried stem, creating a stronger plant.
- Space plants 24 to 36 inches apart so air can circulate and reduce disease risk.
- Water deeply at the base of the plant rather than overhead, and keep the soil consistently moist but not waterlogged during the growing season.
- Determinate (bush) varieties need less space and no staking; indeterminate (vining) varieties need cages or stakes and more room to spread.
Prepare the soil before planting
Tomatoes are heavy feeders—they pull a lot of nutrients from the soil. Before you plant, work compost or aged manure into the top 8 to 10 inches of soil. If your soil is clay-heavy or compacted, add compost to loosen it and improve drainage. Tomatoes don't like soggy roots.
Test your soil pH if you can. Tomatoes prefer slightly acidic soil, around 6.0 to 6.8 pH. If your soil is very alkaline or very acidic, amending it now is easier than trying to fix it later. A straightforward soil test kit from any garden center will tell you where you stand.
If you're planting in containers, use potting soil, not garden soil. Garden soil compacts in a pot and drains poorly. A 5-gallon container is the minimum for a determinate (bush) variety; indeterminate (vining) varieties do better in 10-gallon containers or larger.
Plant the seedling deeper than it came in the pot
This is the single most important planting step for tomatoes. When you remove the seedling from its pot, you'll see a stem with leaves. Bury that stem deeper than it was growing—up to the lowest set of true leaves is fine, or even higher if the seedling is leggy (tall and thin). Any part of the stem that is underground will develop roots.
This deeper planting creates a stronger root system that can support the plant through the growing season and reach water deeper in the soil during dry spells. Remove any leaves that would be buried; they'll rot if they're in contact with soil.
Dig a hole slightly larger than the root ball, set the plant in at the deeper depth, and backfill with soil. Gently firm the soil around the base so the plant stands upright, but don't pack it so hard that you compress the soil and reduce drainage.
Space plants correctly and install support early
Spacing depends on the variety. Determinate (bush) tomatoes stay compact and need 18 to 24 inches between plants. Indeterminate (vining) tomatoes grow tall and sprawling and need 24 to 36 inches. Crowded plants don't get enough air circulation, which leads to fungal diseases like early blight and powdery mildew.
If you're growing indeterminate varieties, install a cage or stake at planting time, not later. Driving a stake or cage into the soil after the plant is established risks damaging the roots. A sturdy cage or a 6-foot stake works well. As the plant grows, loosely tie the main stem to the support with soft ties or strips of cloth—not tight wire that can cut into the stem.
Determinate varieties usually don't need support, though some gardeners stake them anyway to keep fruit off the ground and improve air flow.
Water deeply and consistently after planting
Right after planting, water the soil thoroughly so it settles around the roots and eliminates air pockets. For the first week or two, keep the soil consistently moist (not soggy) as the plant establishes itself.
Once the plant is growing, water deeply at the base of the plant rather than overhead. Overhead watering wets the leaves, which encourages fungal disease. Aim for 1 to 2 inches of water per week, either from rain or irrigation. In hot weather, you may need to water more often. The soil should feel moist 2 to 3 inches down, but not waterlogged.
Mulch around the base of the plant with 2 to 3 inches of compost, straw, or wood chips. Mulch keeps the soil temperature steady, reduces water loss, and prevents soil from splashing onto the leaves during rain or watering—another way to reduce disease.
Harden off seedlings before planting outdoors
If you started your tomato seedlings indoors or bought them from a greenhouse, they're used to stable, protected conditions. Planting them directly outdoors can shock them. Instead, spend 7 to 10 days gradually exposing them to outdoor conditions.
Start by placing seedlings outside in a shaded, sheltered spot for an hour or two. Each day, increase the time outside and gradually move them into more sun and wind. By the end of the week, they should be able to handle a full day outdoors. This process, called hardening off, toughens the plant tissue and reduces transplant stress.
Fertilize after the plant is established
If you worked compost into the soil before planting, your tomato has enough nutrients to get your free guide. Once the plant begins flowering and setting fruit (usually three to four weeks after planting), it will benefit from additional feeding.
Use a balanced fertilizer (like 10-10-10) or a tomato-specific fertilizer according to the package directions. Avoid high-nitrogen fertilizers, which promote leafy growth at the expense of fruit. Side-dress the plant with compost or a slow-release fertilizer, or use a liquid fertilizer every two to three weeks during the growing season.
Frequently Asked Questions
Can I plant tomatoes in the same spot every year?
No. Tomatoes are susceptible to soil-borne diseases like fusarium wilt and verticillium wilt. Plant tomatoes in a different location each year, or rotate them with unrelated crops (lettuce, beans, carrots). If you must plant in the same spot, replace the top 6 inches of soil with fresh compost.
What's the difference between determinate and indeterminate tomatoes?
Determinate varieties grow to a fixed size, stop growing, and produce most of their fruit at once—good for canning. Indeterminate varieties grow continuously throughout the season and produce fruit until frost. Indeterminate plants need more space and support but produce fruit longer.
Should I remove the bottom leaves on my tomato plant?
Once the plant is established and growing, you can remove the lowest leaves (those closest to the soil) to improve air circulation and reduce disease. Wait until the plant is at least 12 inches tall. Remove only a few leaves at a time, and never strip more than one-third of the foliage at once.
How deep should I water my tomatoes?
Water should soak 6 to 8 inches into the soil to reach the root zone. Water slowly at the base so it soaks in rather than running off. A soaker hose or drip line is ideal because it delivers water directly to the roots and keeps the leaves dry.
Can I plant tomatoes in pots on a patio or balcony?
Yes. Use a container at least 5 gallons for determinate varieties and 10 gallons for indeterminate. Make sure the container has drainage holes, use potting soil, and place it where it gets six to eight hours of direct sun. Container plants dry out faster, so check soil moisture daily and water more often than in-ground plants.