Hardiness: All Zones; grow as a winter vegetable in mild areas.
Light: Full sun in cool weather, partial shade in warm weather
Soil: Rich, well-drained; pH 6.0 to 6.8
Water: Need steady, even moisture
- Leaf lettuce:6 to 12 inches (15 to 30 cm) between plants in rows 1 to 3 feet (.30 to 1 m) apart, or plant in large beds with 6 to 9 inches (15 to 23 cm) between plants.
- Head lettuce: 8 to 14 inches (20 to 35 cm) between plants in rows 1 to 3 feet (.30 to 1 m) apart
- Start harvesting leaf lettuce’souter leaves when they are still small to encourage inner leaves to grow. Cut leaf lettuce about 1 inch (2.5 cm) above the soil level leaving plants to regrow another harvest.
- When head lettuce heads are firm, harvest by cutting the plant at ground level
Leaf lettuce is fast and easy to grow. It’s ideal for early and late plantings. Romaine, or Cos lettuce, has long crunchy leaves. Head lettuce forms a dense clump or rosette of leaves. Head or semihead types include iceburg lettuce, and butterhead, or Boston lettuce.
Plant in full sun in cool weather and in partial shade in warm weather. Lettuce will gow in most soils, but does prefer moderately rich, well-drained loam. Cultivate the soil before planting and if planting seeds, rake the surface smooth. Seedling transplants can tolerate a rougher planting bed and area.
Lettuce Planting & Growing Guidelines
Look for heat and bolt-resistant cultivars for summer crops. Also look for disease resistant types. Lettuce does best in air temperatures of 60° to 65° F (16° to 18°C) with soil temperatures a minimum of 35° F (1.7° C); soil any cooler will see slow to no germination. Lettuce seeds germinate best at soil temperatures of 40° to 80° F (4.4° to 27° C), and they won’t germinate at all if the soil temperature is over 85° F (29° C). If the weather gets hot, 80° F (27° C) or warmer, lettuce will bolt (go to seed) and turn bitter.
Direct-sow leafy types two to four weeks before last frost. Barely cover the seeds, because they need light to germinate, and firm the soil with the back of a hoe. Head lettuce types do better as transplants. Start head lettuce seed indoors 6 to 8 weeks before last frost and set out transplants (your own or purchased) 1 to 2 weeks before last frost. For a steady supply of leaf lettuce, plant every 15 to 20 days in the spring and every 10 to 15 days in the summer. Plant head lettuce types at shorter intervals (7 to 10 days). Shade plants in the summer.
If you choose to buy transplants, choose plants that are compact and a dark, or healthy green. When planting, remove several of the outer leaves. They will wilt and die anyway, then water well and mulch generously. Lettuce needs constant moisture for rapid growth and has a very shallow root system, so hand weed carefully. Plants will withstand light to moderate frost if protected with a row cover or other material.
Lettuce grows excellently in containers, so if you have limited space, don’t hesitate to use this form of gardening.
Fertilizer: Lightly broadcast some 10-10-10 over the area, till in, and then plant transplants or sow seeds. When the plants are two weeks old, side-dress with 1 tablespoon (15 ml) per plant of 5-10-10, or one large handful of good compost which generally equals the same. Sprinkle around the base of the plant, but not up against the stem, and water in.
Pest and Disease Prevention: To avoid any chance of soilborne diseases rotate lettuce crops. Control slugs several ways, see our helpful articles next. If you have problems with cutworms, use cutworm collars. After planting, cover plants or seedbed with floating row covers. Covering plants will prevent aphids, leafhoppers, flea beetles and other pests.
Common Problems: Bitter leaves suggest heat and water stress, or overmature lettuce. If your lettuce is getting too old before you can eat it all, plant smaller crops at frequent intervals as mentioned above in the planting guidelines section. During the growing season, keep soil moist, but don’t overwater. Too much water will cause the plants to rot. Always water in the morning so leaves have time to dry by evening and are less prone to becoming diseased.
Days to Maturity: Leaf lettuce: 40 days from seed to harvest. Head lettuce: 70 days from seed to harvest or 20 to 35 days from transplanting to harvest. Leaf lettuces mature most quickly, followed by bibb, romaine and then head lettuce. Head lettuces require a longer season.
Harvest and Storage: Harvest as needed for use. Start harvesting leaf lettuces’ outer leaves when they are still small to encourage inner leaves to grow. Cut leaf lettuce about 1 inch (2.5 cm) above the soil level leaving plants to regrow another harvest. When head lettuce heads are firm, harvest by cutting the plant at ground level. Harvest in the morning and eat it that day. You can store most lettuce in the refrigerator for one to two weeks; iceburg lettuce keeps for up to three weeks.
The lettuce growing information above applies to the following:
Bibb Lettuce (Lactuca sativa) – Also called Boston, butterhead, or cabbage lettuce. Forms loose heads of soft, folded leaves. One of the most popular cultivars is ‘Buttercrunch’.
Iceburg Lettuce (Lactuca sativa) – Also called crisphead or cabbage lettuce. Forms a tight head of crip-textured leaves. Prefers a long, cool, growing season.
Leaf Lettuce (Lactuca sativa) – Also called cutting lettuce or loose leaf lettuce. Instead of heads, it forms loose leaves that may be harvested while quite small. Comes in several red and green leaf varieties.
Romaine Lettuce (Lactuca sativa) – Also called Cos lettuce. Forms an upright, elongated head of crisp, ribbed leaves. Has better heat tolerance than iceburg lettuce.