What is bolting and is it good or bad?

Plants bolt when they sense it’s time to reproduce before unfavorable conditions (like hot weather) kill them.

Bolting is when a plant—usually a leafy green or herb—suddenly sends up a tall flower stalk and starts producing seeds. This often happens prematurely, especially in response to heat, stress, or day length changes, and is considered a survival mechanism to ensure survival.

Is Bolting Good or Bad?
Bad for leafy greens (Lettuce, Spinach, Cilantro, etc.)

• Leaves turn bitter and tough or can be more 'woody'
  
• The plant puts its energy into flowers and seeds instead of leaves.
• Not ideal if you want to harvest tasty leaves.

Good, if what you want are the seeds

• If you want seeds (e.g. coriander from cilantro or dill or mustard seeds), bolting is helpful. Some gardeners let plants bolt intentionally for seed collection.

How to prevent bolting

• Keep plants cool (shade cloth, taller plant nearby to create shade, and mulch). A 30–40% shade cloth can lower leaf temperature significantly.
• Water regularly to reduce stress - keep soil evenly moist
• Harvest leaves regularly (even daily). Frequent harvesting delays flowering. Pinch off any developing flower stalks as soon as you see them (this only delays bolting, but doesn’t prevent it permanently).
• Choose bolt-resistant varieties if available. Look for labels like “slow-bolting” or “heat-tolerant” on seed packets such as  Buttercrunch or Jericho lettuce, Tyee or Bloomsdale Long Standing spinach, and Santo or Slow Bolt cilantro.
• Succession Planting: plant greens in early spring and again in late- summer/early fall for cooler conditions. This way, you avoid the hottest months when bolting is most likely.
• Timing Matters - Plant as early as possible in spring, using covers or cloches to protect young plants from frosts. Aim to get a harvest before summer heat hits, or wait until late-summer/early fall for another round.