Read This Before Adding More Fertilizer
If your plant looks pale, burnt, clawing, yellowing, or “deficient,” pause before increasing nutrients.
Most nutrient problems aren’t caused by a lack of nutrients. They’re usually caused by:
- pH imbalance or lockout
- Overfeeding or salt buildup
- Overwatering
- Poor root oxygen
- Environmental swings
This thread is here to help you diagnose properly instead of guessing.
Quick start:
- Confirm your medium
- Check pH before adjusting feed
- Don’t stack fixes
- Use the template below for accurate help
Want a Clear Answer? Start Here
Copy/paste into your reply:
Medium: soil / coco / hydro
Pot size or system:
Stage: veg / flower (week #)
Watering schedule: frequency + runoff yes/no
Nutrients: brand + dosage
EC/PPM (if known):
Input pH:
Runoff or reservoir pH:
Temps & RH:
What changed in the last 7 days:
Photos: full plant + close leaf + root zone (if possible)
More detail = better answers.
Step 1: Start With Your Medium
Everything depends on what you’re growing in.
Soil
- More forgiving pH range
- Overwatering is common
- Runoff helps, but isn’t exact
Coco
- Behaves closer to hydro
- Needs consistent feeding + runoff
- pH accuracy matters more
Hydro
- pH swings quickly
- EC/PPM becomes critical
- Root health changes fast
If you don’t know your current pH, start there.
Beginner pH overview:
A Beginner’s Guide to pH for Growing Cannabis
Step 2: Check pH Before Touching Nutrients
If pH is out of range, nutrients may be present but unavailable — that’s lockout.
Before adding anything:
- Confirm input pH
- Confirm runoff (soil/coco) or reservoir pH (hydro)
- Make gradual adjustments
Lockout explanation and correction:
Cannabis Nutrient Lockout Guide
Common Nutrient Mistakes
These show up constantly:
“It’s yellow, so it needs nitrogen.”
→ Often watering rhythm or pH.
“Burnt tips mean deficiency.”
→ Usually excess nutrients or salt buildup.
“I’ll flush and then double feed.”
→ Creates instability.
Adding CalMag without confirming pH.
→ Very common.
If multiple deficiency-like symptoms appear at once, it’s usually lockout — not multiple missing nutrients.
Macro/micronutrient basics:
Macro and Micronutrients in Cannabis Cultivation
Watering Often Matters More Than Feeding
Overwatering can cause:
- Oxygen deprivation
- Drooping that mimics deficiency
- Random yellowing
- Poor nutrient uptake
Roots need oxygen as much as nutrients. Before increasing feed strength, confirm the root zone is healthy.
Leaf symptom reference:
Identify Marijuana Plant Problems
Quick Symptom Direction
(Directional only — not a diagnosis.)
- Dark green + clawing down → often overfeeding
- Pale entire plant → check watering and roots first
- Interveinal yellowing → confirm pH before adjusting feed
- Burnt leaf tips → usually excess, not deficiency
Real Nutrient & pH Case Studies From the Forum
If your setup looks similar, these threads are worth reviewing.
pH Lockout
Coco Runoff & Root Zone Drift
EC / PPM Confusion
“CalMag Deficiency” That Wasn’t
- CalMag deficiency despite heavy dosing
- Confirming CalMag deficiency
- CalMag deficiency or something else?
FAQ: Nutrients, pH & Lockout
Why do my plants look deficient even though I’m feeding them?
Most often because pH is out of range, causing lockout.
What are signs of nutrient lockout?
Multiple deficiency-like symptoms at once, stalled growth, worsening despite feeding, and incorrect runoff or reservoir pH.
Should I flush if I suspect lockout?
Sometimes — but confirm pH first. Flushing without understanding the cause can create new issues.
What does nutrient burn look like?
Burnt leaf tips progressing inward, often alongside dark green leaves.
Does coco require different pH management than soil?
Yes. Coco behaves more like hydro and requires tighter pH control and consistent feeding.
Final Reminder
Adding more nutrients rarely fixes nutrient problems.
Accurate diagnosis fixes nutrient problems.
Post your setup below and we’ll work through it properly.