Nature Secret Vault
10 minutes
Bolting Is Premature Flowering Triggered by Day Length and Heat
Spinach bolts as days pass about 13–14 h; lettuce bolts with long days and heat above about 27 °C; cabbage and onion can bolt after a cold spell vernalizes young plants. Above 60°N, as in Tromsø, spinach bolts fast under near-continuous daylight.