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
Measure before you treat
Plant diagnostic essentials
These tools help confirm the cause of ph lockout before you change nutrients, watering, or the environment.
VIVOSUN pH and TDS Meter Combo
Check root-zone pH and nutrient strength before changing a feeding plan.
Check price on AmazonBotanicare Cal-Mag Plus
Useful when filtered water, coco, or a confirmed calcium-magnesium issue is involved.
Check price on AmazonFoxFarm Liquid Nutrient Trio
A complete, staged nutrient system for vegetative growth and flowering.
Check price on AmazonSave the ph lockout recovery plan
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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
Recommended products
Apera pH20 Meter
Accurate digital pH meter — non-negotiable
GH pH Up/Down Kit
Adjust water pH
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:
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