Lettuce
Lactuca sativa
A low rosette of soft, overlapping leaves rising from a single short crown, ranging from tight crisp hearts through upright cos types to loose red-tinged leaf forms. Cut surfaces bleed a white latex that grows bitter once the plant bolts and sends up a branched stem carrying small pale yellow flowerheads. Grown for salad leaves, taken whole or picked leaf by leaf.
A cultivated annual of vegetable beds, allotments, raised beds and containers throughout Britain and Ireland, doing best on moist, fertile soil in cool conditions and bolting quickly in dry heat. Self-sown plants turn up on disturbed ground and compost heaps near where it has been grown, but it does not persist as a naturalised species.
Generally safe eaten raw, and the usual cautions are practical rather than toxicological: wash leaves well, since soil-grown crops hold grit, slugs and, occasionally, the food-poisoning bacteria that have been traced to salad leaves. Bolted plants build up latex and turn strongly bitter, which is unpalatable rather than harmful. Great lettuce (Lactuca virosa) self-seeds on waste and disturbed ground and can pass for a bolted lettuce, but its leaf midrib bears a row of stiff prickles along the underside and its copious latex can cause nausea and drowsiness.
Always use more than one reference to confirm a plant. You are responsible for what you choose to forage.
Growth form
Leaves radiate outwards from one very short, unbranched crown at ground level, so the whole plant lifts as a single rosette. A plant with leaves spaced up a branched, leafy stem is not an unbolted lettuce.
Milky latex
Snapping a leaf base or the stem releases a white sap that dries brownish. It is mild and barely bitter in a young plant; heavy, sticky and strongly bitter latex means the plant has bolted or is a wild Lactuca rather than a salad crop.
Underside of the midrib
Run a finger along the back of the midrib: on cultivated lettuce it is smooth. A line of stiff, backward-pointing prickles there indicates prickly lettuce or great lettuce, not a garden variety.
Bolting and flowers
In heat or long days the crown extends into a branched stem up to about a metre with small pale yellow dandelion-like flowerheads, followed by seeds carried on white parachutes. Leaves picked after this point stay bitter however they are prepared.
Updated 2026-08-08T11:01:30.753Z · Part of the shared Foragers Log catalogue · Vegetable