Why do some seeds need fire to sprout?
Show answer & explanation
Answer: Heat cracks hard seed coats
Fire provides fertilizer ash — Wrong. Ash does fertilize, but many fire-adapted seeds need heat or smoke chemicals to break dormancy, not just nutrients.
Heat cracks hard seed coats ✓ — Correct! Some plants (like sequoias, eucalyptus, lodgepole pine) have hard, resin-sealed seed coats that only crack open after fire's intense heat. This ensures seeds germinate when competition is reduced and nutrients are abundant from ash. It's called serotiny—an adaptation to fire-prone ecosystems!
Smoke signals growth time — Wrong. Some seeds do respond to smoke chemicals, but heat cracking hard coats is the primary mechanism for many fire-dependent species.