Too Much P? (Micronutrient Lockout)
Excess phosphorus can lock out Zn/Fe/Ca and cause dark, clawed leaves.
Phosphorus toxicity? Dark/claw leaves, micronutrient lockout—analyze fast.
Common Causes
- Heavy PK boosters
- Stacking bloom additives
- Feeding high P early
How to Tell Which One You Have
Dark dull leaves, claw, possible Zn/Fe deficiency signs despite high P.
FAQ
Fix?
Reduce P inputs, flush to target EC, rebalance feed.
Add micros?
Yes if Zn/Fe signs persist after lowering P.
pH?
Keep in range to reduce lockout.