WHEN TO PLANT LETTUCE

• Direct sowing in the garden is recommended as soon as the ground can be worked. If you want an earlier crop, however, you can start seeds indoors 4 to 6 weeks before your last spring frost date. Some lettuce seedlings will even tolerate a light frost.
• Lettuce can be sown after soils reach 40°F (4°C), though seeds germinate best at 55 to 65°F (13 to 18°C). Seedlings will typically emerge in 7 to 10 days.
• Nursery-bought transplants should be planted near the last frost-free date for the growing area. Transplants that were started indoors may be planted 2 to 3 weeks earlier after they are properly hardened off.
• After your initial planting, sow additional seeds every 2 weeks in order to have a continuous supply of lettuce.
• In most regions, it’s possible to plant a second crop of lettuce in the fall or even early winter. See our Planting Calendar for planting dates.
• Tip: To plant a fall crop, create cool soil in August by moistening the ground and covering it with a bale of straw. A week later, the soil under the bale will be about 10°F (6°C) cooler than the rest of the garden. Sow a three-foot row of lettuce seeds every couple of weeks—just rotate the straw bale around the garden

CHOOSING AND PREPARING A PLANTING SITE

• Select a sunny spot for the best growth. Ideally, the plants should get at least 6 hours of sun per day, though lettuce will still grow if given less than that.
• The soil should be loose and drain well so that it’s moist without staying soggy.
• To keep the soil fertile, work in composted organic matter about one week before you seed or transplant.
• Since the seed is so small, a well-tilled seedbed is essential. Stones and large clods of dirt will inhibit germination.
• Lettuce does not compete well with weeds. Spacing lettuce close together will help to control weeds. 
• Rotating locations from year to year helps to reduce the occurrence of most diseases.
• Read more about preparing soil for planting.

HOW TO PLANT LETTUCE

• Seeds should be planted â…› to ¼ of an inch deep. Lettuce seeds need light to germinate, so don’t sow them too deep. 
• Seedlings can be thinned when they have 3 to 4 true leaves.
• Transplants should have 4 to 6 mature leaves and a well-developed root system before being planting into the garden.
• For either seeded or transplanted lettuce, leave 12 to 15 inches between each planting row. Here are guidelines for different lettuce types:
  • Loose-leaf lettuce: Plant or thin to 4 inches apart.
  • Romaine (cos) and butterhead (loose-head, Bibb, Boston) lettuce: Plant or thin to 8 inches apart.
  • Crisphead (iceberg) lettuce: Plant or thin to 16 inches apart.
• Water thoroughly at time of transplanting.
• Consider planting rows of chives or garlic between your lettuce to control aphids. They act as “barrier plants” for the lettuce.
• If you’d like to grow your lettuce inside your home, check out these tips for growing lettuce indoors.