Lettuce bolting into flower

Lettuce bolting into flower

© Howard F. Schwartz, Colorado State University

Type: Other

Bolting ( )

Plants are said to 'bolt' when they start flowering before you have had a chance to harvest the roots or leaves that you are growing the plant for. This concentrates the plant's resources on the flower and often leads to toughness or bitterness.


  • Vary from crop to crop but, generally, one or more fast-growing spikes of growth appear which show signs of flower formation

Prevention & control

Causes (and thus things to avoid) vary from crop to crop:
  • Beetroot: low temperatures can cause early sowings to bolt
  • Celery and celeriac: low temperatures (below 12°C), water shortage and root disturbance
  • Onions: Autumn-sown onions which are sown too early
  • Spring and Chinese cabbage: low temperatures (below 10°C) and increasing day length
  • Spinach and lettuce: water shortages and long days
  • In most cases, bolt-resistant varieties are available which cope better with the conditions that normally cause bolting
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    Remove flowering stalks immediately (administrator - 05:50 19/04/2012) Report inappropriate tip
    A fast-growing central stalk growing straight up may well be a flower which will suck energy away from leaf production. Cut and compost as soon as it is clear it's not a leaf.
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