Lettuce is a cool-season crop which must mature before the weather gets warm. Sow lettuce seed indoors 8 to 10 weeks before the average last frost date in spring; transplant seedlings to the garden when they are about 4 inches tall. Direct sow lettuce in the garden 4 to 6 weeks before the average last frost date. Lettuce will be ready for harvest 65 to 80 days after sowing depending on variety.
Description. Lettuce is a fast-growing, hardy annual with either loose or compactly growing leaves that range in color from light green to reddish brown.
• Leaf or Looseleaf lettuce form leaves in a loose circular pattern; leaves are yellow, green, red, or purplish. Looseleaf lettuce comes to harvest in 40 to 50 days.
• Butterhead or Bibb lettuce form loose round heads with delicate green to cream-colored leaves at the center. Bibb lettuce comes to maturity in 65 to 80 days.
• Romaine or Cos lettuce form leafy green upright cylindrical or oval heads. Romaine lettuce comes to maturity in 80 to 85 days.
• Crisphead or Iceberg lettuce form firm, compact heads of pale green leaves. Crisphead lettuce comes to harvest in 80 to 90 days.
• Celtuce or Stem lettuce form loose leafy tops on stalks that resemble celery. Leaves are eaten as greens and stalks are eaten like celery. Celtuce comes to harvest in 65 to 90 days.
Yield. Plant 6 to 10 heads per person in the household.
Site. Grow lettuce in full sun or partial shade. Lettuce prefers well-worked, well-drained soil that is moisture retentive. Add aged compost to planting beds in advance of planting. Lettuce prefers a soil pH of 6.0 to 6.8.
Planting time. Lettuce is a cool-season crop which must come to harvest before the weather gets warm. Sow lettuce seed indoors 8 to 10 weeks before the average last frost date in spring; transplant seedlings to the garden when they are about 4 inches tall. Direct sow lettuce in the garden 4 to 6 weeks before the average last frost date. Lettuce will be ready for harvest 65 to 80 days after sowing depending on variety. In regions where the weather warms quickly, start lettuce indoors to get a jump on the season. Sow lettuce in succession. In a mild-winter climates grow lettuce for crops in spring, fall, and winter.
How to plant. Lettuce needs well-worked soil with good drainage and moisture retention. When you are preparing the soil dig in a complete well balanced fertilizer.
Planting and spacing. Sow lettuce seeds ¼ inch deep in wide rows. Thin leaf lettuce seedlings to stand 6 to 8 inches apart and head lettuce to 12 inches apart. Space rows 18 inches apart. Lettuce must be thinned; lettuce that is too crowded will bolt.
Water and feeding. Keep planting beds evenly moist but not soggy. Do not let shallow-rooted lettuce plants dry out. Regular, even watering is needed to form heads. Avoid splashing muddy water on lettuce plants. Use a light mulch to keep muddy soil off the leaves. Add aged compost to planting beds before planting and again as a side dressing at midseason.
Companion plants. Carrots, cucumbers, radishes, strawberries.
Care. Long hot sunny days will cause lettuce to become bitter and bolt and go to seed. Use shade cloth to partially protect lettuce from warm weather. (Place bitter tasting lettuce in the refrigerator for two and it will taste less bitter.) Protect lettuce from frost with cloches or row covers.
Container growing. Lettuce grows well in containers. Grow a single head of lettuce in a 6 inch container; set lettuce in larger containers on 10-inch centers. Lettuce is heat sensitive so move containers to cooler spots if the temperature rises.
Pests. Lettuce can be attacked by aphids, cutworms, slugs, and snails. Spray aphids way with water; put a collar around each plant to discourage cutworms; trap slugs and snails with a saucer of stale beer set flush to the soil.
Diseases. Lettuce has no serious disease problems.
Harvest. Cut outer leaves on a cut-and-come-again basis and allow inner leaves to develop, or harvest the whole plant at once by cutting it off at ground level. Harvest lettuce in the cool part of the day so that it does not wilt immediately. Chilling will crisp up wilted leaves.
Varieties. There are dozens of varieties of each type of lettuce. Ask your cooperative extension for specific recommendation for your region.
• Crisphead or iceberg: Great Lakes (90 days);
• Butterhead: Summer Bibb (62 days); Buttercrunch (75 days).
• Leaf: Black-Seeded Simpson (45 days); Ruby (45 days); Red Sails (45 days).
• Cos or Romaine: Parris Island Cos (73 days).
• Celtuce (80 days).
Storing and preserving. Lettuce will keep in the refrigerator for up to 2 weeks.
Common name. Lettuce, crisphead lettuce, Butterhead lettuce, stem lettuce (celtuce), leaf lettuce, cos, romaine
Botanical name. Lactuca sativa
Origin. Near East