Nutrient IssuesSerious
pH Lockout in Cannabis
When your water or soil pH is outside the plant's absorption range, roots can't take up nutrients — even if there's plenty available. This looks like multiple deficiencies at once.
What it looks like
- ●Multiple symptoms at once (yellowing + spots + slow growth)
- ●You're feeding, but plant looks starved
- ●Runoff pH outside 6.0-6.8 (soil) or 5.5-6.5 (coco/hydro)
Quick diagnostic checks
1Get a pH meter TODAY — this is a non-negotiable tool
2pH all water before it touches the plant
3Flush and reset at the first sign of lockout
Causes ranked by likelihood
1. Water pH not adjusted
Most commonSigns
- ●Tap water not pH'd before feeding
Fix
- ✓pH all water to 6.5 (soil) or 6.0 (coco) before feeding
- ✓Use pH Up/Down drops to adjust
2. Salt buildup shifting soil pH
CommonSigns
- ●Runoff pH different from input pH
- ●Many feedings without a flush
Fix
- ✓Flush with 3x pot volume of pH 6.5 water
⚠️When to worry
pH lockout is usually the root cause when multiple deficiencies show up at once. Always check pH first.
Gear that prevents this problem
The right equipment stops most grow problems before they start. Start here:
Not sure what you're looking at?
Upload a photo of your plant and our AI will diagnose the problem in seconds — free.
Open AI Plant Diagnosis →Get Your Free Grow Checklist
Download our free printable checklist covering everything from seed to harvest. Perfect for first-time growers!
No spam, ever. Unsubscribe anytime.