The Growing Season Depends on Your Frost Dates

You can grow tomatoes outdoors only after the last frost date in your area has passed. Tomatoes are warm-season plants that die if exposed to freezing temperatures. The last frost date varies by region — it might be mid-April in the South, late May in the North, or even early June in cold climates. You can find your local last frost date by searching "last frost date" plus your zip code, or by contacting your county extension office.

Once soil temperatures reach 60°F (ideally 70°F or warmer), you can transplant seedlings outdoors. If you start seeds indoors, begin them 6 to 8 weeks before your last frost date so they are ready to move outside at the right time. Direct seeding tomatoes into the garden works too, but only after the soil has warmed — usually 1 to 2 weeks after your last frost date.

Key Takeaways

  • Tomatoes cannot survive frost, so you must wait until after your area's last frost date to plant them outdoors.
  • Soil temperature matters as much as air temperature — tomato roots need soil at least 60°F, preferably 70°F or warmer.
  • If you start seeds indoors, sow them 6 to 8 weeks before your last frost date so seedlings are ready when outdoor conditions are safe.
  • In warm climates with mild winters, you can grow tomatoes in fall and winter instead of spring and summer.
  • Tomatoes need 60 to 85 days from planting to first harvest, depending on the variety you choose.

Spring Planting in Cold and Moderate Climates

In most of the United States, spring is the main tomato-growing season. Plant transplants or seeds after your last frost date and once soil has warmed. In the upper Midwest and Northeast, this usually falls between late May and early June. In the mid-Atlantic and upper South, it is typically mid-to-late April. In the Deep South and Southwest, spring planting can happen as early as late February or March.

Tomatoes planted in spring will flower and fruit through summer and into early fall. Harvest continues until the first fall frost kills the plant. In most regions, this gives you a 3- to 4-month growing window. If you live in a short-season area, choose early-maturing varieties (60 to 70 days to harvest) rather than long-season types (80+ days), so you have time to pick ripe fruit before frost arrives.

Fall and Winter Growing in Warm Climates

If you live in a warm climate — southern Florida, southern California, southern Texas, or similar regions where winter temperatures rarely drop below 50°F — you can grow tomatoes in fall and winter instead. Plant in late summer or early fall (August through September) so plants mature as temperatures cool. Fall-planted tomatoes often produce better fruit than spring-planted ones in very hot climates, because they avoid the intense heat of midsummer.

In these regions, spring is actually the off-season for tomato growing. Temperatures climb too high, humidity spikes, and plants struggle with heat stress and disease. Check your local extension office for the exact planting window in your area, because the timing varies significantly even within warm states.

Starting Seeds Indoors vs. Direct Seeding

Starting seeds indoors gives you more control and a longer harvest window. Sow seeds indoors 6 to 8 weeks before your last frost date in a warm spot (70°F to 75°F is ideal). Keep seedlings under grow lights or on a sunny windowsill. Transplant them into larger containers if they get leggy. Harden them off — gradually expose them to outdoor conditions — for 7 to 10 days before moving them to the garden.

Direct seeding (planting seeds straight into the garden) works if you have a long growing season. Wait until soil is at least 70°F and all frost danger has passed. Direct-seeded tomatoes will mature 1 to 2 weeks later than transplants, so this method works best in regions with 80+ frost-free days. In short-season areas, starting indoors is usually necessary to get a harvest before fall frost.

Temperature and Daylight Needs Throughout the Season

Tomatoes grow best when daytime temperatures stay between 70°F and 85°F. They slow down below 60°F and above 95°F. Nighttime temperatures below 55°F can cause flowers to drop without setting fruit, even if daytime warmth is fine. This is why late spring plantings sometimes produce slowly at first — nights are still cool.

Tomatoes also need full sun: at least 6 to 8 hours of direct sunlight daily, though 8 to 10 hours is better. They flower and fruit more reliably with plenty of light. In very hot climates, afternoon shade can prevent sunscald on fruit, but the plant still needs morning sun. Daylight length does not affect tomato flowering the way it does for some other crops, so you can grow them successfully even as days shorten in late summer and fall.

Extending Your Harvest Before the First Frost

If you live in a region with an early fall frost, you can extend your harvest by a few weeks. Plant early-maturing varieties, use black plastic mulch or landscape fabric to warm the soil, and plant as soon as conditions allow in spring. Prune suckers (side shoots) on indeterminate varieties to direct energy into ripening fruit rather than new growth. Stop fertilizing 4 to 6 weeks before your expected first frost date so the plant focuses on finishing existing fruit rather than producing new flowers.

As temperatures drop in fall, you can pick green tomatoes and ripen them indoors. Tomatoes picked at the "breaker stage" (when the first blush of color appears) will ripen in a warm room over 1 to 2 weeks. This lets you salvage fruit that would otherwise be lost to frost. Store them at room temperature — refrigeration stops the ripening process.

Choosing Varieties Based on Your Growing Season Length

Tomato varieties are labeled by days to maturity, which tells you how long from transplanting to first ripe fruit. Early varieties mature in 60 to 70 days; mid-season varieties in 70 to 80 days; late varieties in 80+ days. Count backward from your first expected fall frost to see how many frost-free days you have, then choose varieties that will mature within that window.

Determinate (bush) tomatoes produce most of their fruit in a short window, usually 3 to 4 weeks. They are good for canning or if you want a concentrated harvest. Indeterminate (vining) tomatoes produce fruit continuously until frost kills the plant, giving you a longer harvest period. In short-season areas, indeterminate varieties can be risky because they may not have time to mature all their fruit. In long-season areas, indeterminate varieties let you harvest from midsummer through fall.

Frequently Asked Questions

Can I plant tomatoes before the last frost date if I use row covers?

Row covers provide some frost protection, but they only buy you a few degrees and a few days. Tomatoes are sensitive to cold soil as well as cold air, so covers do not solve the soil temperature problem. It is safer to wait until soil has warmed naturally. If you want to plant early, use black plastic mulch to warm the soil for 2 to 3 weeks before planting, then transplant under row covers once soil reaches 60°F.

What if my area has unpredictable spring weather with late frosts?

Wait until 1 to 2 weeks after your average last frost date rather than planting right on that date. Late frosts do happen, and losing transplants to an unexpected freeze is costly. If you have already planted and frost is forecast, water the soil thoroughly the day before (moist soil holds heat better), and cover plants with blankets or row covers on frost nights.

Can I grow tomatoes indoors year-round?

Yes, with grow lights and controlled temperature. Indoors, you can grow tomatoes in containers under lights set to 14 to 16 hours daily. Keep temperatures between 70°F and 80°F during the day and above 60°F at night. You will need to hand-pollinate flowers with a small brush or vibrating device since there are no bees indoors. Indoor tomatoes produce less fruit than outdoor plants but can give you harvests outside the normal season.

How do I know when to start seeds if I do not know my last frost date?

Search online for "last frost date" plus your zip code, or call your county extension office — they have this data for your specific area. Once you know the date, count back 6 to 8 weeks and mark that on your calendar as your seed-starting date. If you are unsure, starting seeds 8 weeks early is safer than starting too late, because you can keep seedlings in containers longer if needed.

Do I need to wait for warm soil if I am using transplants from a nursery?

Transplants are more cold-tolerant than seeds, but they still need warm soil to establish roots and grow. Planting a healthy transplant into cold soil (below 60°F) slows growth and can cause root rot. Wait until soil has warmed, even if air temperatures are comfortable. You can speed soil warming by laying black plastic mulch over the bed for 2 to 3 weeks before planting.