Bolting is the premature transition of a vegetable plant from vegetative growth to flowering and seed production, triggered by environmental stresses such as high temperatures, long day-length, or drought. In leafy crops like lettuce, spinach, and herbs, bolting makes the leaves bitter and tough, rendering the harvest unpalatable.
Key Facts
- Triggered by high temperatures (above 24Β°C / 75Β°F for lettuce), long days, or water stress
- Plant shifts energy from leaf production to flowering and seed set
- Leaves become bitter, tough, and unsuitable for fresh eating
- Bolted plants develop a central flower stalk (called a scape in some crops)
- Prevention: maintain cool temperatures, use short-day or heat-tolerant varieties
- Indoor growing advantage: controlled photoperiod and temperature prevents bolting year-round