Crisp, tender lettuce is perhaps the most desirable of all salad plants. For the best flavor and texture, it is best grown with close attention to moisture, soil, and climatic requirements. Lettuce was originally a Eurasian annual; it has been developed into many varieties and cultivars with dozens of forms.
For the home gardener lettuce is generally divided into three categories: (1) tight, crisp, nearly white head lettuce with a cabbage-like head; (2) loose, so-called leaf lettuce, where although there is a head, it is looser, and with many more outer green leaves; (3) Cos or Romaine lettuce, which is cylindric, has long, relatively loose leaves and so forms a head which sometimes needs to be tied up.
Of the three categories, the first is the most difficult to grow; the second is easy to grow and a good choice for beginners, and the third is also easy to grow and can stand up to summer heat.
Lettuce is a cool season crop (except Cos) and is commonly planted in early spring and late summer. (In the South and California, lettuce is often grown in winter.) Most lettuce varieties must mature before the weather gets warm. Midsummer heat, more than other things will cause lettuce to flower. That ruins the chance of heading because the tall flower stalk is forced up through what should be the head. There are bolt-resistant, heat-tolerant varieties for growing in warm weather.
Here is your complete guide to growing lettuce!
Quick Lettuce Growing Tips
- Sow lettuce seeds indoors 4 to 6 weeks before the average last frost date in spring; transplant seedlings to the garden when they are about 4 inches (10cm) tall.
- Direct sow lettuce in the garden in early spring 4 weeks before the average last frost date when the soil temperature is at least 35°F (1.7°C).
- Sow lettuce again when the weather cools in late summer or fall.
- Where the weather stays mild or warm most of the year, grow bolt-resistant, heat-tolerant varieties. Most lettuce seed packets will give the heat tolerance of the variety or cultivar.
- In regions where the weather gets cold in winter, time for lettuce planting to bring the crop to harvest before the first fall frost or grow lettuce through the winter under a plastic tunnel or cold frame.
- Lettuce will be ready for harvest 65 to 80 days after sowing depending on the variety.
- In hot summer regions, time lettuce planting so that the harvest comes in late spring or in autumn.
Types of Lettuce
Lettuce is a fast-growing, hardy annual with either loose or compact growing leaves that range in color from light green to reddish-brown.
- Leaf or Looseleaf lettuce forms loose, circular patterns, and compact heads; leaves are yellow, green, red, or purplish; leaves can be frilly or smooth. Looseleaf lettuce comes to harvest in 40 to 50 days.
- Butterhead lettuce also called Bibb letuce or Boston lettuce, forms loose round heads with delicate green to cream-colored leaves at the center. Butterhead lettuce has a soft buttery texture and delicate flavor. Butterhead lettuce comes to maturity in 65 to 80 days; it can be very sensitive to high and low temperatures.
- Romaine or Cos lettuce form leafy green upright cylindrical or oval heads. Romaine lettuce comes to maturity in 80 to 85 days. Romaine lettuce is easy to grow.
- Crisphead or Iceberg lettuce form firm, compact heads of pale green, overlapping leaves. Crisphead lettuce comes to harvest in 80 to 90 days. Crisphead lettuce requires more space than other types of lettuce and can be finicky when it comes to water.
- Celtuce or Stem lettuce forms 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.
Where to Grow Lettuce
- Grow lettuce in full sun or partial shade. Use shade cloth to protect lettuce from very warm or hot weather.
- Lettuce prefers well-worked, well-drained soil that is rich in organic matter and moisture retentive. Sandy loam is the best choice of soil to grow lettuce. (Some varieties, like Grand Rapids, do best in heavy soil with considerable clay in them.)
- Add 4 inches (10cm) or more of aged compost or commercial organic planting mix to planting beds in advance of planting. Turn the soil to 6 inches (15cm) deep.
- Lettuce prefers a soil pH of 6.0 to 6.8. Lettuce soil should not be acid. If a soil test find that the soil is acid, it should be limed.
- More important than texture is soil moisture.
Lettuce Planting Times Through the Year
- Lettuce is a cool-season crop that must come to harvest before the weather gets warm.
- Sowing lettuce seed should be timed so that they are transplanted to the garden just as soon as the ground can be worked. You need not wait for the last frost of spring in order to set out the seedlings, because, especially in their early stages with will easily endure several degrees of light frost.
- Sow lettuce seed indoors 4 to 6 weeks before you plan to set transplants in the garden—commonly 4 to 6 weeks before the last frost in spring. You can even begin sooner if you like, up to 10 weeks before the last frost.
- Transplant seedlings to the garden when they are about 4 inches tall but not before night temperatures remain above 30°F (-1.1°C).
- Direct sow lettuce in the garden when the soil temperature is at least 35°F (1.7°C) Lettuce seed will not germinate in soil cooler than 35°F (1.7°C).
- Sow lettuce every three weeks for a continuous harvest. As temperatures warm sow bolt-resistant, heat-tolerant varieties.
- Eight weeks before the first expected frost in autumn, switch back to cool-weather lettuce varieties.
- In mild-winter regions, grow lettuce from autumn through winter into spring. Sow succession crops every three weeks through the winter.
- Lettuce will be ready for harvest 65 to 80 days after sowing depending on the variety.
Starting Lettuce Plants Indoors
- Sow lettuce seeds ¼ inch (6mm) deep; cover with finely listed soil. Sow bolt-resistant lettuce ½ inch (12mm) deep.
- Seeds can be broadcast in flats or sown in tiny drills in flats.
- To prevent soil crusting, sprinkle finely sifted compost or organic potting soil over the seeds.
- Place seeded flats under a grow light or in a bright window. Turn flats of young plants every couple of days for even growth.
- In a few days, the plant will be up and as soon as they are 2 inches high with true leaves; they must be pricked-out and spaced about 2 inches in each way. A second and third spacing is advised.
- Plant 6 to 10 heads per person in the household.
Planting Lettuce Outdoors
- Young lettuce seedlings are best set out in the garden on an overcast day; in any case, thy should be watered until they recover from the move.
- Direct sow lettuce in the garden after indoor started plants have been set out.
- Lettuce seeds sown outdoors can be broadcast or in very shallow drills; in either case covered very lightly with the finest soil.
- Slightly tamp the soil and water it with a fine mist like spray (a hose spray without a fine nozzle will wash out the seeds).
- The seeds will come up too thick for permanent spacing; they can be thinned as noted above.
- Outdoor sown seed will provide a good crops aft there indoor started plants have been harvested.
- Succession planting can follow beginning about 12 days after the first outdoor sowing.
Thinning and Spacing Lettuce in the Garden
- Thin leaf lettuce seedlings from 6 to 8 inches (15-20cm) apart and head lettuce to 12 inches (30cm) apart.
- Space rows 18 inches (45cm) apart.
- Square feet planting: 6 loose leaf plants per square foot, 1 heading lettuce plant per square foot.
- Lettuce must be thinned; lettuce that is too crowded will bolt.
- Transplant rooted thinnings to another row or spot; transplanted lettuce will be set back a couple of weeks but it will come to harvest.
Fall Crop Lettuce
- For a fall lettuce crop, follow the same procedure for the early crop of indoor seedlings, except that the flats are put outdoors in a cool, shaded place.
- Young plants should be ready to set out about August 15 in northern regions.
More tips: Lettuce Seed Starting Tips.
Container Growing Lettuce
- Lettuce grows well in containers or grow bags. Lettuce makes an attractive addition to a tower garden.
- Grow a single head of lettuce in a 6-inch (15cm) container; set lettuce in larger containers on 10-inch centers.
- Lettuce is heat sensitive so move containers to cooler spots if the temperature rises.
Companion Plants for Lettuce
- Grow lettuce with carrots, cucumbers, radishes, strawberries, and herbs including cilantro.
- Plenty of soil moisture will help induce rapid growth; slow-growing lettuce will not taste good.
- Lettuce has a shallow root system; do not let plants dry out. Keep the garden bed evenly moist but not soggy.
- Regular, even watering is required to form heads.
- If the rain comes to the garden often mulch with straw around the base of plants to keep muddy soil off the leaves.
- A sign that lettuce is not getting enough water is growing of leaf tips, called tip burn.
- Lettuce grows best in soil rich in plant food.
- Add aged manure to the lettuce planting bed in advance of planting. Aged manure adds much huus to the soil and thus heightens its moisture-holding capacity as well as enriching it. Turn the manure into the soil so that there is a fine tilth.
- Additionally, feed lettuce with compost tea or manure tea every two weeks throughout the season.
- You can also feed lettuce with aged compost or a commercial organic planting mix added as a mulch or side dressing around plants.
More on how to grow lettuce: Lettuce Growing Tips.
- Long hot sunny days and high temperature (80 to 90 degrees F) will cause lettuce to bolt–send up a flower stalk–and go to seed. After bolting, leaves will be bitter-flavored.
- Use shade cloth to partially protect lettuce from warm weather and extreme light intensity. (Place bitter-tasting lettuce in the refrigerator for two and it will taste less bitter.)
- Protect lettuce from cold nights or frost with cloches or row covers.
About lettuce and heat: Lettuce Bolting.
- Lettuce can be attacked by aphids, cutworms, leafminers, cabbage loopers, 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.
- Spray cabbage loopers with Bacillus thuringiensis or neem oil.
- Leafminers are the larvae of a fly; exclude the fly from laying eggs by protecting plants with floating row covers. Pick off and destroy leaves with leafminer tunnels.
- Lettuce has no serious disease problems.
- Root and collar rot can occur where the soil stays wet.
More tips: Lettuce Growing Problems: Troubleshooting.
Harvesting and Storing Lettuce
- For the best flavor and crisp texture pick lettuce when you need it and use fresh lettuce right away.
- For loose-leaf varieties, cut outer leaves on a cut-and-come-again basis and allow inner leaves to remain and develop. You can harvest the whole plant at once by cutting it off at ground level.
- Harvest crisphead, cos, and butterhead lettuce when the heads are firm and mature. You can lift the entire plant or cut heads at the crown just above soil line. Where heads are cut at the crown, smaller leaves will grow for a second harvest.
- Harvest lettuce in the cool part of the day so that it does not wilt immediately. Chilling will crisp up wilted leaves.
Storing and Preserving Lettuce
- Crisphead lettuce will keep in the refrigerator for up to 3 weeks.
- Loose-leaf, butterhead, and romaine lettuce will keep in the refrigerator for 2 weeks.
Lettuce in the Kitchen
- Lettuce is usually eaten raw in sales or sandwiches, but can also be quickly cooked.
More tips: How to Harvest and Store Lettuce.
Lettuce Frequently Asked Questions
Q: How can I have fresh, tender lettuce all season long?
A: Sow a short row of lettuce seeds every 7 to 10 days. This will ensure new plants will be available regularly.
Q: Should lettuce be started indoors?
A: Lettuce is a crop that is easily started from seed indoors. Start seeds in flats or pots for transplanting into the garden. Begin transplanting as soon as the ground is workable in spring and the last hard freeze has passed.
Q: Can I grow lettuce where summers are hot?
A: In hot summer regions, grow lettuce in spring and fall. To grow lettuce in summer in hot regions, plant in a partially shaded area or use a 50 percent shade cloth screen from 10 a.m. to 4 p.m. In hot areas, plant bolt-resistant varieties that are bread to endure hot spells, not continuous hot weather.
Q: Does lettuce need a lot of water?
A: Perhaps the most important thing lettuce plants need is a constant supply of water. Without water, lettuce can be bitter tasting. Moisten the soil whenever it is the slightest bit dry.
Q: What is the best way to harvest lettuce? What does “cut-and-come-again” mean?
A: Lettuce can be harvested by cutting heads back to just above the roots. If you leave the stump and roots in place, the plants will produce a smaller crop of leaves. Cut-and-come-again means to cut or harvest a few leaves at a time; this method is used with loose-leaf lettuces. Once the plant is about 6 inches tall, you can cut off the outermost leaves for fresh use leaving the remaining leaves to grow on for harvest at a later time.
Lettuce Varieties to Grow
There are dozens of varieties of each type of lettuce. Ask your cooperative extension for specific recommendations and best options for your region. Here are varieties often grown in the home garden:
- Loose-Leaf: ‘Black-Seeded Simpson’ (45 days); ‘Grand Rapids’ (45 days); ‘Oakleaf’ (50 days); ‘Salad Bowl’ (45 days); ‘Ruby’ (45 days); ‘Red Sails’ (45 days), ‘Tango’, ‘Slobolt’.
- Butterhead: ‘Big Boston’ (75 days); ‘Buttercrunch’ (75 days); ‘Summer Bibb’ (62 days); ‘Ermosa’; ‘Esmeralda’; ‘Nancy’.
- Romaine or Cos: ‘Parris Island Cos’ (73 days); ‘Valmain’ (85 days); ‘Green Towers’; ‘Valley Heart’; ‘Red Eyes Cos’, ‘Red Romaine’.
- Crisphead or iceberg: ‘Great Lakes’ (95 days); ‘Ithaca’ (75 days); ‘Iceberg’; ‘Crispivo’.
- Celtuce or stem lettuce (80 days). Botanical name Lactuca sativa var. augustana is grown for its succulent thick stem and tender leaves.
Lettuce types explained: Five Types of Lettuce.
- Common name: Lettuce, crisphead lettuce, Butterhead lettuce, stem lettuce (celtuce), leaf lettuce, cos, romaine
- Botanical name: Lactuca sativa
- Family: Asteraceae (Compositae)
- Origin: Near East
More tips: How to Grow a Salad Garden