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Lettuce

Lactuca sativa

VegetableCool-seasonContainer-friendly Easy

Quick, cool-season, and perfect for containers. The seed needs light to germinate and stalls in heat, so sow it shallow, keep it cool, and harvest outer leaves for a steady supply.

Growing conditions

Light
Full sun to part shade — about 6 hours of direct sun in cool weather; light afternoon shade is welcome in late spring and summer to slow bolting
Water
Medium
Soil
Well-drained, fertile loam to sandy loam high in organic matter; shallow roots need steady moisture · pH 6.0–6.8 (slightly acidic to neutral)
When to sow
Begin direct sowing 2–4 weeks before the last spring frost; set out hardened-off transplants around 3–4 weeks before last frost (well-hardened plants tolerate brief dips to about -6°C / 20°F). For a fall crop, sow 6–8 weeks before the first fall frost. Lettuce takes light frost but not a hard freeze unprotected.
Spacing
Leaf, romaine and butterhead 20–30 cm (8–12 in) in rows 30–45 cm (12–18 in); crisphead/iceberg 25–38 cm (10–15 in) in rows 45–75 cm (18–30 in); baby-leaf cut-and-come-again much denser
Days to maturity
30–80 days (leaf and baby-leaf 30–45 days; butterhead and romaine 50–70 days; crisphead/iceberg 65–80 days)
Hardiness
Grown in USDA zones 2–11 as a cool-season crop. Time it to the cool windows: zones 2–6 spring and late summer/fall; zones 7–8 early spring, fall, and into winter under cover; zones 9–11 mostly fall through early spring (avoid summer heat).

How to grow it

  1. 1

    Sow shallow and keep it light

    Lettuce seed needs light to , so press it into firmed soil and cover with no more than 0.6–1 cm (1/4–3/8 in) of fine soil or vermiculite. Keep the surface evenly moist and cool until seedlings emerge, usually in 2–10 days.

  2. 2

    Thin and transplant to give heads room

    Once seedlings have a few true leaves, thin leaf types to 20–25 cm (8–10 in) and heading types to 25–38 cm (10–15 in). Eat the thinnings. To get an earlier, more uniform crop you can instead start in cell trays, off over about a week, and .

  3. 3

    Water steadily and shallowly often

    Lettuce is over 90% water with a shallow root system, so keep the top of the soil consistently moist with about 2.5 cm (1 in) of water per week. Even moisture is the single biggest defense against bitterness, , and tipburn.

  4. 4

    Mulch and feed lightly

    A thin of straw or keeps roots cool, holds moisture, and keeps grit off the leaves. Lettuce is a light feeder that grows fast — work compost in before planting and side-dress or with a balanced nitrogen source once or twice during growth to keep leaves tender.

  5. 5

    Sow in succession for a steady supply

    Lettuce matures fast and then , so don't plant it all at once. Sow a short row every 2–3 weeks ( sowing), and shift to bolt- and heat-tolerant varieties as spring warms toward summer.

  6. 6

    Beat the heat to prevent bolting

    When days lengthen and temperatures stay above about 27°C (80°F), lettuce — it sends up a flower stalk and the leaves turn bitter. Use shade cloth or part shade, keep plants well watered, and harvest before hot weather peaks. Once a plant bolts, the bitterness won't reverse.

Gardener's notes

  • Lettuce is positively photoblastic — the seed needs light to — so a too-deep, too-dark sowing is the most common cause of 'bad seed' that actually wasn't.
  • Tipburn and most bitterness are watering and heat problems, not or soil-calcium problems; even moisture fixes more lettuce troubles than any feeding.
  • For summer sowings, start seed indoors somewhere cool or pre-chill it — modern cultivars go dormant above about 27°C (80°F), which is why midsummer direct sowings so often fail to come up.

Varieties worth knowing

Buttercrunch (butterhead)
Reliable, heat-tolerant bibb type with a buttery tender heart; an AAS winner and a classic beginner pick.
Black-Seeded Simpson (leaf)
Fast, frilly light-green looseleaf, ~45 days; cut-and-come-again favorite for early and repeat sowings.
Parris Island Cos (romaine)
Upright, dependable green romaine with good disease tolerance; widely grown for full heads or hearts.
Muir (summer crisp / Batavia)
One of the most heat- and bolt-tolerant types; holds well into warm weather when most lettuce gives up.
Salad Bowl (oakleaf leaf)
Loose, lobed rosette, slow to bolt and slow to turn bitter; comes in green and red and tolerates some heat.
Great Lakes (crisphead/iceberg)
Classic firm-heading iceberg, more heat-tolerant than most crispheads but still the longest and fussiest type to grow.

Common problems & fixes

Bolting (premature flowering)
Sign: Plant stretches tall, the center elongates into a stalk, and leaves turn bitter and milky.
Fix: Plant in the cool shoulders of the season, choose slow-bolt/heat-tolerant varieties, provide afternoon shade and steady water, and harvest promptly. Bitterness is permanent once bolting starts.
Tipburn
Sign: Brown, scorched, dead margins on the youngest inner leaves, often hidden inside a forming head.
Fix: A calcium-delivery problem driven by uneven moisture and fast growth, not by low soil calcium. Keep moisture even, avoid drought spikes and over-fertilizing, and grow tipburn-tolerant varieties — calcium sprays rarely help home gardeners.
Aphids
Sign: Clusters of tiny green or gray insects on undersides and in leaf folds, with sticky residue and curled leaves.
Fix: Blast off with water, encourage ladybugs and hoverflies with flowering companions, and use insecticidal soap if needed. Float row cover over young plants; check inner leaves before eating since aphids hide deep in heads.
Slugs and snails
Sign: Ragged holes in leaves and slime trails, worst in cool, damp, mulched beds.
Fix: Hand-pick at night, set beer traps, keep mulch pulled back from stems, and use iron-phosphate bait if pressure is high.
Downy mildew & gray mold (Botrytis)
Sign: Pale yellow patches with fuzzy growth underneath (downy mildew) or fuzzy gray rot on crowded, wet plants (Botrytis).
Fix: Space for airflow, water at the base in the morning, avoid overhead watering late in the day, and remove infected leaves and debris.

Companions

Grows well with
CarrotsRadishesBeetsOnions and chivesStrawberriesPole beans (for light shade)Marigolds and dill (draw in aphid predators)
Keep apart from
Brassicas like broccoli and cabbage (heavy feeders that crowd and shade)Fennel (allelopathic to many vegetables)Parsley (can shade and compete as it bushes out)

Harvest & storage

Harvest
Pick leaf lettuce as cut-and-come-again — snip outer leaves about 2.5 cm (1 in) above the crown and the plant keeps producing — or cut the whole rosette at the base. Harvest heading types (butterhead, romaine, crisphead) when the head feels firm and full. Cut in the cool of early morning when leaves are crisp and sweetest, before the day heats up or the plant bolts.
Storage
Lettuce does not cure or store long. Rinse, spin or pat dry, wrap loosely in a towel or perforated bag, and refrigerate at about 0–2°C (32–36°F) and high humidity for up to 7–10 days. Keep it away from apples, bananas and tomatoes — their ethylene makes lettuce brown and spot faster.

Sources

This guide is curated from authoritative horticulture references — primarily US university Extension services, the USDA, and the RHS.