Lettuce: plant running up to flower before it is ready to eat

What it is likely to be on lettuce

1. Bolting

   Candidate 1very common on this plant

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Bolting

   Checked 2026-08-13

   A plant switching from leaf or root production to flowering and seed. It is the plant doing exactly what it evolved to do under stress, and it cannot be reversed — which makes bolting a problem of timing and cultivar choice rather than of treatment.

   Points towards it

   • · heat is the usual trigger, and lettuce responds to it within days
   • · a check from drying out brings it on as reliably as heat does
   • · a growing-season problem

   Argues against it

   • · a recent repot points to transplant check rather than to the plant deciding to flower

   Check this next

   Look at the centre of the plant. A lettuce running a stem up from the middle, or an onion sending up a thick round flower stalk, has bolted — and no amount of watering reverses it once the stem has started.

   What to do now

   Harvest what is usable now rather than waiting: a bolted lettuce turns bitter within days, and a bolted onion will not store. Sow successionally and keep the crop evenly watered to reduce it next time — bolting is a response to a check, not a disease.

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Bolting

   Checked 2026-08-13

2. Transplant shock

   Candidate 2common on this plant

   ·source

   Sourced guidancemoderate confidence

   • Royal Horticultural Society: Transplanting

   Checked 2026-08-13

   Wilting, leaf drop or a stall in growth in the days after repotting, planting out or moving. Often not a problem at all but a normal adjustment, and the commonest mistake is to react to it by changing something else — which turns a recoverable check into a real decline.

   Points towards it

   • · a check at transplanting is a distinct trigger from heat, and it acts weeks earlier in the season
   • · it follows planting out from modules or a seedbed

   Argues against it

   • · hot weather is the commoner trigger and points to ordinary bolting rather than to a transplant check
   • · the plant has not been moved, so a transplant check cannot be the trigger — this rules it out entirely.

   Check this next

   Work out when it was moved. A crop that runs to seed within a few weeks of being planted out, before any hot spell, was checked at transplanting — root disturbance and a dry fortnight afterwards do it as reliably as heat.

   What to do now

   Nothing rescues the affected plants; harvest what is usable. Next time sow direct where the crop is to grow, or plant out earlier and smaller and water well for the first fortnight — the aim is to avoid the check rather than to treat the result.

   ·source

   Sourced guidancemoderate confidence

   • Royal Horticultural Society: Transplanting

   Checked 2026-08-13

Narrow it down

This page lists everything at once, which is the right shape for reading and the wrong shape for deciding. The interactive tool asks one question at a time, starting with whichever would separate these causes fastest, and stops as soon as further answers would not help.

Opens with the plant and the symptom already set. Nothing you answer is stored or sent anywhere — the answers live in the address bar and nowhere else.

What this does not cover

These are the causes GrowingHQ holds rules for on lettuce — not every cause there is. Where several problems look alike, the honest answer is often that they cannot be told apart by eye, and a page that named one would be guessing. If none of the above fits, the general plant running up to flower before it is ready to eat page lists causes across all plants, and the Lettuce profile lists the problems it is prone to.