How to Grow Lettuce: Sowing to Salad in Six Weeks

Lettuce might be the most rewarding thing you can grow: seed to salad in six weeks, no special kit, and happy in a window box, a raised bed, or the corner of any border. It's also a cool-season crop, which means right now — as summer heat fades — is one of the two best sowing windows of the whole year. Here's the full growing guide.

Pick your type

• Loose-leaf (oak leaf, 'Salad Bowl', 'Lollo Rossa'): the fastest and most forgiving — around 40–50 days to maturity, and pickable much earlier as baby leaves. Best for cut-and-come-again.
• Butterhead ('Tom Thumb', 'Marvel of Four Seasons'): soft, folded heads in roughly 55–65 days; tolerates slightly poorer conditions than crisp types.
• Cos / romaine ('Little Gem', 'Lobjoits Green'): upright, crunchy heads in about 60–70 days; 'Little Gem' is quicker and brilliant for small spaces.
• Crisphead / iceberg: dense, crisp heads but the slowest (70–80 days) and fussiest about heat — the hardest for beginners.

When to sow

Lettuce germinates in cool soil — anywhere from about 4°C, with the ideal range roughly 10–20°C. Above about 25°C seed goes thermally dormant and germination gets patchy, which is why midsummer sowings so often fail. That gives you two windows: early spring, and late summer into autumn. A September sowing hits the sweet spot: warm soil, cooling air, and fewer bolting problems. Quick loose-leaf types sown now crop through autumn; sow cold-hardy varieties like 'Winter Density' or 'Arctic King' in early autumn and they'll stand through winter under a cloche or fleece for extra-early spring salads.

Sowing and spacing

Sow thinly, about 1 cm deep, directly where plants will grow, or into modules for transplanting after 3–4 weeks. For full heads, thin or plant to roughly 15–25 cm apart for leaf, cos and butterhead types, and 30 cm for crisphead, in rows 30 cm apart. For baby-leaf salad, skip the spacing entirely: broadcast seed thickly in a band and harvest young. Sow a short row every 2–3 weeks rather than one big batch — lettuce doesn't wait for you, and succession sowing keeps the salad bowl full instead of feast-then-famine.

Care: water little and often

Lettuce is shallow-rooted and about 95% water, so steady moisture is the whole game. Frequent, light watering keeps growth fast, tender and sweet; drought stress makes leaves bitter and pushes plants towards bolting. Grow it in fertile soil enriched with compost, and it will rarely need extra feeding — though a nitrogen-rich liquid feed can perk up a cut-and-come-again patch between harvests.

Bolting: why lettuce turns bitter

When days lengthen and temperatures climb, lettuce switches from making leaves to making a flower stalk — bolting — and the sap turns bitter. Once a plant stretches upward and the leaves taste sharp, pull it and re-sow. To delay bolting: keep soil consistently moist, pick heat-resistant varieties for summer sowings, and give summer crops light afternoon shade. Autumn sowings largely dodge the problem, which is another reason September lettuce is such easy lettuce.

Pests

• Slugs and snails are enemy number one, especially on seedlings — night patrols, beer traps and copper tape around containers all help.
• Aphids cluster on soft leaves; blast them off with water or use insecticidal soap.
• Birds sometimes strip seedlings; net new sowings if pigeons visit your garden.

Tip: growing in containers sidesteps most slug pressure and lets you move autumn lettuce to the sunniest, most sheltered spot as the season turns.

Harvesting

For heads, cut at the base when firm and full. For cut-and-come-again, start when leaves reach 8–10 cm: either pick outer leaves and let the centre keep producing, or shear the whole patch 2–3 cm above the crown with scissors — it regrows for another cutting or two, 2–3 weeks apart. Harvest in the morning, when leaves are at their crispest.

Warning: don't cut into or below the growing crown when shearing a cut-and-come-again patch — cut too low and the plant won't regrow.

Growing lettuce in autumn and winter

As light fades, growth slows but doesn't stop. Cloches, cold frames or fleece keep quality up and keep the worst weather off; hardy varieties will sit almost still through midwinter and then explode into growth at the first hint of spring — weeks ahead of anything sown next year.

Spot something odd on your lettuce — holes, spots, or a mystery seedling that might be a weed? Photograph it with PlantMe and the app will identify it and flag likely problems before they spread through the row.