Loose-leaf lettuce

Origin & history

All garden lettuce descends from wild lettuce (Lactuca serriola), a plant of the Mediterranean and Western Asia; the Egyptians were growing it more than 4,000 years ago and the Romans carried it north over the Alps. The pickable leaf lettuces are the older form — firm heads were only bred out from the 16th century onwards. The genus name Lactuca comes from the Latin lac, milk: snap a lettuce stem and white sap runs out.

Varieties

Oak leaf, Lollo Bionda and Lollo Rossa differ mainly in leaf shape and colour; red-leaved varieties grow a little more slowly but usually stand longer before they bolt. Batavia types form loose heads and cope best with heat. Ready-made cutting and baby-leaf mixes are sown thickly in a band and harvested with scissors. Loose-leaf lettuce is self-pollinating and almost always open-pollinated — saving your own seed works without any trouble.

Care

Thin to 15 cm even if it looks too generous: plants standing too close stay small and rot in the heart. Lettuce is shallow-rooted and needs even moisture — better a thorough soaking every second day than a daily splash, and always at the base rather than over the leaves. It is a light feeder and needs no nitrogen; a handful of mature compost when the bed is prepared covers the whole crop. Sow a short new row every two to three weeks and the supply never breaks off.

What can go wrong

Downy mildew is the commonest fungal attack: yellow patches bounded by the leaf veins, with a grey-white bloom underneath, encouraged by crowding and leaves that stay wet overnight. Space more widely, water at the base in the morning, take out affected leaves and choose varieties explicitly sold as mildew-tolerant. Slugs go for young seedlings first — plants already 10 cm across come through far better, and an evening round with a bucket does more than anything else in wet weeks. Brown, dried-out leaf margins are not a pathogen but the result of uneven watering.

Harvest, storage & kitchen

Pick early in the morning while the leaves are turgid — cut at midday, lettuce is already half wilted. Wash only just before eating and spin it thoroughly dry; stored wet it goes glassy within hours. Limp leaves usually recover in cold water. Wrapped in a damp cloth a portion keeps two or three days in the fridge; beyond that it is not worth keeping.

Frequently asked questions

Is loose-leaf lettuce winter hardy?

No, it is not winter hardy. It takes light frosts in spring and autumn, and fleece can stretch picking into November, but a properly frozen winter outdoors ends the crop.

When can I sow loose-leaf lettuce?

Direct sow from mid-March to early September and pick from late April to early November. Press the seed onto the soil rather than covering it, and reckon on six to eight weeks to the first cut, with summer sowings a little quicker.

Why does my loose-leaf lettuce taste bitter?

Usually because it is about to flower: warmth, long days and dry soil push it into a flower stalk and the leaves turn bitter. Pick the rest quickly and put the next batch somewhere shadier for summer.

How often can I cut loose-leaf lettuce?

Either way works: pick just the outer leaves and one plant keeps giving for four to six weeks. Cut the whole row about four centimetres above the soil and it regrows two or three times, with two to three weeks between cuts. After that the leaves come noticeably smaller.

Will loose-leaf lettuce grow in a window box?

Yes, a box about 20 cm deep is enough. Space the plants 15 cm apart, water onto the soil in the morning and keep the box out of full midday sun, where it bolts much sooner.