Cold Stress on Cannabis? (Low Temperature Damage)
Cold temps slow growth, cause purpling, and stress plants. Below 60°F (15°C) is problematic for most strains.
Cold stress on cannabis? Purple and slow growth—see causes and analyze fast.
Common Causes
- Night temps too low
- Cold root zone
- Outdoor late season
- AC too strong
How to Tell Which One You Have
Purple/red stems and leaves (not genetics), slow growth, drooping, yellowing. Worse in mornings.
FAQ
Is purple always cold?
No, some strains purple naturally. But if sudden + slow growth, likely cold.
Damage permanent?
Growth resumes when warmed. Severe cold can cause permanent stunting.
Fix?
Raise temps above 65°F, insulate pots, reduce night temp drop.