When to Plant Lettuce

Lettuce timing comes down to temperature. The plant is happiest when days average 60 to 70°F (Illinois Extension), can take a light frost, and turns bitter and bolts in heat. So the goal is to plant early enough that the crop matures before summer, or late enough that it matures as fall cools down. The dates for your zone above turn that into a calendar. This page explains the reasons so you can adjust for the weather you actually get.

Spring: direct sowing

Extension services agree that lettuce goes in before the last frost, but they differ on how early:

• Utah State: sow 2 to 3 weeks before the last frost.
• NC State: sow 2 weeks before the last frost.
• Illinois and Maryland: sow leaf and butterhead types as soon as the soil can be worked and is dry enough to rake.

The soil sets the real start date. Utah State says lettuce can be sown once the soil reaches 40°F, with the best germination at 55 to 65°F and seedlings appearing in 7 to 10 days. UW-Madison’s chart gives a slightly higher 45°F minimum. Below those temperatures, seed sits in the ground and germinates slowly. UW-Madison suggests measuring at 2 inches deep, between 10 a.m. and noon, on three days in a row. That tells you whether the soil is ready, whatever the calendar says.

Young plants handle cold well. Utah State says temperatures down to 32°F don’t seriously damage them, and Maryland says lettuce needs protection only from heavy frost or a hard freeze. Keep a row cover on hand for cold snaps after sowing.

Spring: transplants

Transplants give an earlier harvest and are the most reliable way to grow crisphead outside regions with long, cool springs. Start them indoors before the last frost. NC State says 6 to 8 weeks ahead. Utah State and UGA say 5 to 6 weeks is enough. Maryland notes that even 3- to 4-week-old transplants give an earlier harvest. UGA adds that seedlings grown in an unheated cold frame can take 10 to 12 weeks.

Harden them off outdoors for 4 to 5 days (UGA), then set them out near the last frost date (Utah State). Illinois says not to let growth stop entirely during hardening.

Keep sowing, then stop before the heat

For a steady supply, sow a short row every 2 weeks (NC State) or every 10 to 14 days (Illinois). Illinois advises wrapping up spring sowings at least a month before the hot days of early summer. A crop started later than that usually hits heat just as it matures, and long days plus warm temperatures trigger bolting.

If you want to push into early summer, choose slow-bolting varieties. Then sow where tall crops such as sweet corn, staked tomatoes or pole beans will shade the lettuce in the afternoon, or use shade cloth (Maryland).

Fall: count back from the first frost

Fall lettuce often tastes better than spring lettuce because it matures into cooling weather. Crisphead in particular does better in fall in many areas (Illinois). There are two ways to time it:

• Utah State: pick early varieties and sow 50 to 75 days before your target harvest date, aiming for the crop to mature 1 to 2 weeks before the first fall frost.
• NC State: sow about 3 months before the first frost.

Both methods land in late summer, when the soil is often hotter than 80°F, the point where Utah State says germination drops. Sow in a shaded spot or start seedlings somewhere cool and shaded, keep the seedbed moist, and transplant once they are established. Plants handle light frost at the end of the season, and row covers or a cold frame can extend the harvest further (Maryland).

Regional advice varies. Clemson lists fall lettuce as not recommended in the South Carolina Piedmont, while the Coastal Plain gets both a spring and a fall planting. Maryland goes the other direction: healthy three-week-old transplants set out around mid-October can survive winter with protection and produce an early spring crop.

Warm-winter areas: fall through late winter

In zones 9 to 11, lettuce is a cool-season crop that runs from late summer or fall into late winter, not a spring crop. UF/IFAS plants it from fall through winter in Central and South Florida, but North Florida’s window is late winter into early spring. The University of Arizona’s Maricopa County calendar starts seeding in the Phoenix low desert in late summer. Texas A&M’s average fall dates for leaf lettuce in zones 9a and 9b fall in late fall and early winter. UF/IFAS adds that crisphead succeeds only in Florida’s coolest months, so grow leaf types there. Exact months are in the dates for your zone above.

In Georgia, UGA recommends planting in early fall or early spring and skipping head lettuce, which doesn’t handle the climate.

Quick checks before you sow

• Soil at 40 to 45°F or warmer, and not above 80°F.
• At least a month before regular hot weather in spring, or early enough in late summer to mature before hard freezes.
• Fresh seed. Illinois says lettuce seed doesn’t keep well. Buy new seed each spring and keep any seed for fall sealed in the refrigerator.