Plant tomatoes after your last spring frost, when soil reaches 60°F

The best time to grow tomatoes is after the danger of frost has passed and soil temperature climbs to at least 60°F—ideally 65°F or warmer. Tomatoes are warm-season plants that will not germinate, grow, or produce fruit in cold soil. Planting too early is the most common mistake home gardeners make; a tomato seed or seedling in cold, wet ground will sit dormant, rot, or grow so slowly that you lose weeks of growing time.

Your last spring frost date is the key number. This is the average date when frost stops occurring in your area. You can find yours by entering your zip code at planthardiness.ars.usda.gov or asking your local cooperative extension office. Once you know that date, wait until one to two weeks after it before transplanting seedlings outdoors. If you are starting from seed indoors, count backward six to eight weeks from that date to know when to start seeds under lights.

Key Takeaways

  • Tomatoes need soil temperature of at least 60°F to germinate and grow; planting in cold soil causes seeds to rot or seedlings to stall.
  • Find your last spring frost date using your zip code at the USDA Plant Hardiness Zone map, then wait one to two weeks after that date to transplant outdoors.
  • Start seeds indoors six to eight weeks before your last frost date if you want larger plants ready to transplant in spring.
  • In hot climates, you can plant a second crop in mid-to-late summer for a fall harvest before the first frost arrives.

Spring planting: timing seedlings and direct seeding

If you are buying seedlings from a nursery or garden center, look for plants that are 6 to 8 inches tall with thick stems and healthy green leaves. Avoid tall, spindly seedlings that have been kept indoors too long. Harden them off by setting them outside in a sheltered spot for a few hours each day, gradually increasing time outside over seven to ten days. This acclimates them to wind, direct sun, and temperature swings before you plant them in the ground.

Direct seeding—planting seeds straight into the garden—works in warm climates where the growing season is long. Wait until soil is consistently above 65°F and all frost danger has passed. Plant seeds half an inch deep, keep soil moist, and expect germination in five to ten days. Direct seeding saves money but gives you a later harvest than transplanting, since seedlings started indoors are already weeks ahead.

Summer planting for a fall crop

In regions with hot summers and mild falls, you can plant a second crop of tomatoes in mid-to-late summer for harvest in autumn. Count backward from your first fall frost date—the average date when frost returns in your area—and plant seedlings or seeds so they mature before that date arrives. Most tomato varieties need 60 to 85 days from transplant to first ripe fruit, depending on the variety.

Summer-planted tomatoes often produce better in fall because they avoid the intense heat of peak summer, which can cause flower drop and sunscald. Water consistently during the hot months leading up to planting, and choose varieties labeled as heat-tolerant if you are planting in July or early August. Check your seed packet or plant label for days to maturity, then work backward from your first frost date to confirm you have enough time.

Soil temperature matters more than air temperature

A warm day does not mean the soil is warm. Soil heats up more slowly than air, especially in spring when the ground has been cold all winter. Use a soil thermometer—available at any garden center for under $10—to check soil temperature at a depth of 4 inches. This is the most reliable way to know if conditions are right for planting.

If you plant when soil is below 60°F, seeds will sit in the ground for weeks without sprouting, and seedlings will grow very slowly or rot. Waiting two more weeks for soil to warm up is always faster than planting too early. You can speed up soil warming by laying black plastic or landscape fabric over the bed for a week or two before planting, which traps heat from the sun.

Regional timing examples

In the northern United States (zones 3 to 5), last spring frost typically falls between May 1 and May 31. Plant seedlings outdoors in mid-to-late May, or start seeds indoors in March. The growing season is short, so choose early-maturing varieties that produce fruit in 60 to 70 days.

In the mid-Atlantic and Midwest (zones 5 to 6), last frost is usually April 15 to May 15. Transplant seedlings in late April or early May. You may have time for a small fall crop if you plant seedlings in late July, though frost often arrives before fruit fully ripens.

In the South and warm regions (zones 7 to 9), last spring frost comes in March or early April. Plant in early April for a summer harvest, then plant again in July or August for a fall crop that often produces better quality fruit. Winter frost arrives later, giving you a longer fall growing window.

Choosing varieties based on your growing season length

Tomato varieties mature at different speeds. Early varieties like 'Siberia', 'Early Girl', and 'Glacier' produce fruit in 50 to 65 days and are essential in short-season regions. Mid-season varieties like 'Brandywine' and 'Cherokee Purple' need 70 to 85 days. Late-season varieties like 'Sungold' and 'San Marzano' may need 80 to 90 days or more.

Count the number of frost-free days in your region—the span between your last spring frost and your first fall frost. If you have 100 frost-free days, you can grow any variety. If you have only 80 days, stick to early and mid-season types. Check your seed packet or plant label for "days to maturity" and choose varieties that will finish before frost arrives.

Common mistakes that delay harvest

Planting too early is the biggest mistake. Cold soil stops growth, and a seedling planted in April in a 50°F soil will not catch up to one planted in May in 65°F soil. The May planting will overtake it within weeks. Patience pays off.

Buying seedlings that are already flowering or fruiting is another error. These plants are stressed and often produce less total fruit than younger, healthier transplants. Choose stocky green plants with no flowers yet.

Ignoring your frost dates and planting by the calendar instead of by temperature is also common. Frost dates vary year to year. A warm March does not mean frost will not return in April. Always check soil temperature before planting, and watch the forecast for unexpected cold snaps even after you have transplanted.

Frequently Asked Questions

Can I plant tomatoes in April if the weather is warm?

Not reliably. A warm day does not mean soil is warm. Soil temperature at 4 inches deep is what matters. If soil is below 60°F, seeds will rot and seedlings will stall. Use a soil thermometer to check before planting, even if the air temperature feels warm.

What happens if I plant tomatoes before the last frost date?

A late frost will kill seedlings or young plants. Even if frost does not kill them, cold soil slows growth so much that you lose weeks of production time. Waiting until after the frost date and soil warms up is faster overall.

How do I know my last spring frost date?

Enter your zip code at planthardiness.ars.usda.gov, or call your local cooperative extension office. They can give you the average date for your area. Remember it is an average—frost can occur a week or two before or after that date in any given year.

Can I plant tomatoes in summer if I missed spring planting?

Yes, if you have time before fall frost. Count backward from your first fall frost date. Most varieties need 60 to 85 days to produce ripe fruit. If you have at least that many days left before frost, plant seedlings in mid-to-late summer for a fall harvest.

Do all tomato varieties take the same number of days to mature?

No. Early varieties mature in 50 to 65 days, mid-season in 70 to 85 days, and late-season in 80 to 90 days or more. Check your seed packet or plant label for "days to maturity" and choose varieties that will finish before your first fall frost arrives.