Lettuce Growing Guide

With the variety of colors, shapes and flavors available, your salads may never be the same. Lettuce is can adapt to many growing conditions, but likes it cool - around 60 F to 65 F. Grow in spring and fall, and slow bolting by shading summer crops.

Site Characteristics

Sunlight:
„ full sun
„ part shade
Yields best in full sun. Part shade helpful when it’s hot.
Soil conditions:
„ requires well-drained soil
Tolerant of a wide range of soils, but prefers well-drained, cool, loose soil with plentiful moisture and pH 6.2 to 6.8. Sensitive to low pH. Lime to at least 6.0.
Special locations:
„ outdoor containers

Plant Traits

Lifecycle: annual
Ease-of-care: easy
Height: 0.5 to 2 feet
Spread: 0.5 to 2 feet

Foliage color:
„ light green
„ medium green
„ dark green
„ red
„ purple
„ variegated
Foliage texture: medium
Shape: cushion, mound or clump
Romaine (Cos) varieties tend toward upright.
Tolerates:
„ frost - Will withstand light to moderate frost. Hardened seedlings more tolerant than mature plants.

Growing Information

How to plant:
Propagate by seed
Germination temperature: 40 F to 85 F - Seed can go dormant at high temperatures. Best germination is below 70 F.
Days to emergence: 7 to 14 - Germinates in about a week at 50 F, 2 days at 70 F.
Seed can be saved 1 year.

Maintenance and care

Direct seed or transplant in early spring, as soon as you can work the soil. To get an early start, prepare beds the previous fall by working in manure or compost and raking smooth to leave a fine seedbed.
Direct-seeding: Sow seed 1/8 inch deep, 1 inch apart in rows 12 to 18 inches apart. When plants have two or three true leaves, thin to 12-inch spacings for crisp-head varieties, 6 to 10 inches for other types. You can also lightly broadcast seed (particularly of loose-leaf varieties) in a patch instead of a row.
Transplants: Sow in 1-inch cells 3 to 4 weeks before transplanting outside. Harden seedlings by reducing water and temperature for 3 days before transplanting. Hardened plants should survive 20 F. Space crisp-head transplants 12 inches apart in rows 18 inches apart.

Space other varieties 6 to 10 inches apart in rows 12 to 18 inches apart. Seeds need light to germinate, so do not plant too deep. Make succession plantings every week or two. Grow several varieties with different maturity dates for a continuous supply.

Lettuce has a shallow root system. Keep soil moist to keep plants growing continuously. Mulch to retain moisture and suppress weeds (unless slugs are a problem).

Moisture stress and high temperatures, particularly at night, encourage bolting. As the season progresses, plant more bolt-resistant varieties. Locate plants where they will be partially shaded by taller nearby plants, latticework or other screen.

Use row covers to protect very early plantings from cold, to protect young plants from insects, and (supported by hoops) to shade crops when warm weather arrives.

For fall crops, time maturity around time of first expected frost. Mature plants aren’t as tolerant of freezing as seedlings.

Pests

Aphids, Leafminers, Leafhoppers, Cabbage loopers, Cutworms, Wireworms, Slugs

Diseases

Damping off, Downy mildew, Mosaic, Fusarium

Varieties

There are five main types of lettuce:

Looseleaf (var. crispa) - Easy to grow. Matures quickly. You can start harvesting leaves as soon as 4 weeks after planting. Great for early-season plantings. Wide variety of leaf shapes and colors. 45 to 60 days to full maturity.
Butterhead (bib, loosehead, Boston) - Exceptionally good flavor and quality. Forms loose heads with oily leaves. 55 to 75 days to maturity.
Romaine (Cos, var. longfolia) - Upright, elongated heads. (Some grow nearly 2 feet tall.) More tolerant of warm weather and less likely to bolt than other lettuce types. Red varieties as well as traditional light green. Most take about 70 days to mature.
French (summer crisp) - Midway between butterhead and crisphead. You can harvest early like leaf lettuce or wait until heads form. 50 to 75 days.
Crisphead (iceberg, var. capitata) - The familiar spherical heads found in grocery stores. Most difficult varieties to grow. Requires long cool season. Best chance of success is by setting out transplants in early spring. Will bolt quickly in response to stress. 75 or more days.
Choose slow-bolting varieties for later plantings that may encounter hot weather.