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Lettuce

When to Plant

  • 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 close to your last frost-free date. 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 another 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 late 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 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.

How to Plant

  • Seeds should be planted 1/8 to 1/4 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.

How to Grow

  • Fertilize 3 weeks after transplanting. Lettuce prefers soil that is high in organic material, with plenty of compost and a steady supply of nitrogen to keep if growing fast. Use organic alfalfa meal or a slow-release fertilizer.

  • Make sure the soil remains moist but not overly wet. It should drain well.

  • Lettuce will tell you when it needs water. Just look at it! If the leaves are wilting, sprinkle them anytime—even in the heat of the day—to cool them off and slow down the transpiration rate. Using row covers can also help to keep lettuce from drying out in the sun. 

  • An organic mulch will help conserve moisture, suppress weeds, and keep soil temperatures cool throughout the warmer months.

  • Weed by hand if necessary, but be careful of damaging your lettuce plants' roots; they are shallow.

  • Bolting is a common problem that's caused by warm temperatures (over 70°F / 20°C) or changes in day length. When a lettuce plant bolts, it starts to produce a central stem and seed stalk, and leaves take on a bitter flavor. 

  • To delay bolting, cover plants with a shade cloth so that they get filtered light. Be sure to maintain watering throughout the warmest parts of the growing season, too.

  • Planning your garden so that lettuce will be in the shade of taller plants, such as tomatoes or sweet corn, may reduce bolting in the heat of the summer.

Pests/Diseases

  • Aphids

  • Cutworms

  • Earwigs

  • Powdery Mildew

  • Lettuce Mosaic Virus

  • Slugs/Snails

  • White Mold

  • Whiteflies

  • Woodchucks

  • Rabbits

How to Harvest

  • Lettuce should be harvested when full size, but just before maturity. The leaves taste best when they're still young and tender.

  • Before maturity, you can harvest leaf lettuce by simply removing outer leaves so that the center leaves can continue to grow.

    • Butterhead, romaine, and loose-leaf types can be harvested by removing the outer leaves, digging up the whole plant, or cutting the plant about an inch above the soil surface. A second harvest is often possible when using the first or third methods.

    • Crisphead lettuce is picked when the center is firm.

  • Mature lettuce gets bitter and woody and will go bad quickly, so check your garden everyday for ready-to-harvest leaves.

  • It’s best to harvest lettuce in the morning before leaves have been exposed to sun, as they will be the most crisp at this time.

  • As time passes and the plant loses vigor, you may be better off planting a second round of seeds than waiting for new leaves.

  • Keep lettuce in the refrigerator for up to 10 days in a loose plastic bag.

  • Lettuce leaves have wilted? Put the leaves in a bowl of cold water with ice cubes and soak for about 15 minutes.