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Bolting
EnvironmentalMedium impact
Bolting is the premature production of a flowering stem, triggered by temperature stress, day length, or drought. Once a plant bolts, leaf and root quality declines rapidly and the crop becomes bitter or tough. It is particularly common in early sowings exposed to cold followed by warmth.
Key facts
- Type
- Environmental
- Affects
- Beetroot · Lettuce · Spring-onion
- Active season
- Apr - Aug
- Peak season
- May - Jul
- Vulnerable stages
- Sown · Growing
- If confirmed
- Act soon
Signs & symptoms
- -central stem elongating rapidly and unexpectedly
- -flower buds or open flowers forming before the crop is ready
- -leaves becoming tough, bitter, or reduced in size
- -on beetroot: woody roots and a tall, branched central stem
- -on lettuce: tight central point elongating before hearting
Management
Do now
- -Harvest immediately once bolting is detected - quality deteriorates quickly
- -Remove bolted plants promptly to free up space and prevent self-seeding
Prevention
- -Choose bolt-resistant varieties, especially for early or late-season sowings
- -Avoid sowing too early in cold conditions - temperature fluctuation is a key trigger
- -Succession sow in small batches and harvest promptly - leaving plants to overmature in warm weather accelerates bolting
- -Maintain consistent soil moisture - drought stress accelerates bolting
Resistant varieties
Further reading
- -Bolting is triggered by vernalisation (cold exposure followed by warmth) or long days - it is a survival response, not a disease
- -Some crops like beetroot are more prone when sown before the soil has warmed sufficiently