Lettuce is a fast-growing annual leaf vegetable grown in cool weather for raw salads and other dishes. It does best in full sun or light shade in cool conditions, as heat makes it bolt.
Family
Asteraceae (Daisy family)
Grows as
Annual
Light
Full sun, Part shade
Water
Keep soil evenly moist; consistent water prevents bitterness and bolting.
Soil
Loose, fertile, well-drained soil with nitrogen-rich compost, pH about 6.0 to 6.8.
Temperature
16–18 °C preferred; performs poorly above 24 °C; tolerates about 7 °C; hardy annual that can overwinter under straw in mild areas.
How easy
Easy
Safety
Not known to be toxic
Edible
Yes, some parts
Native range
as a cultigen from W. Asia
Climate
temperate
About
Lettuce (Lactuca sativa) is an annual plant of the family Asteraceae mostly grown as a leaf vegetable. The leaves are most often used raw in green salads, although lettuce is also seen in other kinds of food, such as sandwiches, wraps and soups; it can also be grilled. Its stem and seeds are sometimes used; celtuce (asparagus lettuce) is one variety grown for its stems, which are eaten either raw or cooked. In addition to its main use as a leafy green, it has also gathered religious and medicinal significance over centuries of human consumption. Europe and North America originally dominated the market for lettuce, but by the late 20th century the consumption of lettuce had spread throughout the world. In 2023, world production of lettuce (and chicory) was 28 million tonnes, led by China with 53% of the total.
How to grow it
A hardy annual, some varieties of lettuce can be overwintered even in relatively cold climates under a layer of straw, and older, heirloom varieties are often grown in cold frames. Lettuces meant for the cutting of individual leaves are generally planted straight into the garden in thick rows. Heading varieties of lettuces are commonly started in flats, then transplanted to individual spots, usually 20 to 36 cm (7.9 to 14.2 in) apart, in the garden after developing several leaves. Lettuce spaced farther apart receives more sunlight, which improves color and nutrient quantities in the leaves. Pale to white lettuce, such as the centers in some iceberg lettuce, contain few nutrients.
Lettuce grows best in full sun in loose, nitrogen-rich soils with a pH of between 6.0 and 6.8. Heat generally prompts lettuce to bolt, with most varieties growing poorly above 24 °C (75 °F); cool temperatures prompt better performance, with 16 to 18 °C (61 to 64 °F) being preferred and as low as 7 °C (45 °F) being tolerated.
Uses
Raw iceberg lettuce is 96% water, 3% carbohydrates, and contains negligible protein and fat (table). In a reference amount of 100 grams (3.5 oz), iceberg lettuce supplies 14 calories and is a rich source (20% or more of the Daily Value, DV) of vitamin K (20% DV), with no other micronutrients in significant content (table).
Text excerpted from the Wikipedia article Lettuce by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
Life form, climate and native range: World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 3.0), reformatted; see Plants of the World Online.