Nitrogen Toxicity in Cannabis? (Dark Green Clawing)
Nitrogen toxicity makes leaves go dark, shiny, and clawed. Heat, light, and overwatering can look similar, so confirm before flushing.
Nitrogen toxicity in cannabis? Dark green clawing leaves and shiny tips—see causes, confirm the issue, and analyze your plant in seconds.
Common Causes
- Overfed veg nutrients or too-strong feed
- Slow drybacks causing EC creep
- Cold root zone slowing uptake
- pH drift locking other nutrients
How to Tell Which One You Have
Look for dark, glossy leaves with downward tips, especially on newer growth. If lower leaves are pale, it may be imbalance, not pure excess N.
FAQ
Should I flush immediately?
Only if runoff EC is high or leaves are very dark and clawed. Otherwise, reduce N and increase runoff slightly.
Can light burn mimic N toxicity?
Yes. Light stress hits tops first; N toxicity often shows uniformly dark foliage.
Will nitrogen toxicity stunt buds?
Yes, excess N in flower can delay ripening and reduce aroma.