Practical Troubleshooting Flowchart (Substrate & Glasshouse Crops)
This page helps diagnose common problems using observed symptoms, not assumptions.
Work from top to bottom. Do not skip steps.
Step 1 — Is uptake behaving normally?
Check:
- Is irrigation volume normal?
- Is drainage occurring as expected?
- Is drain EC stable week-to-week?
If YES → go to Step 2
If NO → go to Step 1A
Step 1A — Uptake has dropped or stalled
Common causes:
- Root-zone oxygen limitation
- Excessive VPD (afternoon stress)
- Sudden EC increase
- Temperature extremes (hot days / warm nights)
Actions:
- Check drainage percentage
- Check substrate moisture pattern
- Check afternoon leaf posture
- Avoid increasing EC until uptake recovers
Do not push feed to fix low uptake.
Step 2 — Is drain EC rising?
If YES → go to Step 2A
If NO → go to Step 3
Step 2A — Rising drain EC
Common causes:
- Insufficient drainage
- Sodium / chloride accumulation
- Climate stress limiting uptake
- Excessive EC target
Actions:
- Increase drainage fraction slightly
- Check raw water sodium and chloride
- Confirm EC trend over several days
- Avoid rapid EC reductions
Rising EC is usually a symptom, not the cause.
Step 3 — Are visual symptoms present?
If YES → go to Step 4
If NO → monitor, do not intervene
Step 4 — Identify symptom type
A) Leaf edge burn / tip burn / blossom end rot
Likely causes:
- Low transpiration (high humidity / low VPD)
- Transport limitation, not Ca deficiency
- Root stress
Actions:
- Improve drying and airflow
- Avoid raising calcium blindly
- Stabilise climate
B) Interveinal chlorosis (young leaves)
Likely causes:
- Iron or manganese availability
- High pH or bicarbonate
- Root-zone stress
Actions:
- Check pH trend
- Review chelate choice
- Check raw water alkalinity
C) Wilting with moist substrate
Likely causes:
- Excessive VPD
- Root oxygen limitation
- Heat stress
Actions:
- Review afternoon VPD
- Improve airflow / shading
- Check root health
D) Soft growth / stretching
Likely causes:
- Warm nights
- Low radiation
- Excess nitrogen
Actions:
- Reduce night temperature slightly
- Avoid pushing feed
- Improve light capture if possible
E) General yellowing (older leaves)
Likely causes:
- Nitrogen limitation
- Root restriction
- Prolonged stress memory
Actions:
- Confirm uptake trend
- Avoid large nitrogen jumps
- Allow recovery time
Step 5 — Did you change something recently?
If YES:
- Expect recovery lag
- Observe for several days before changing again
If NO:
- Look upstream (climate, roots, water)
Step 6 — Sanity checks before adjusting feed
Before changing recipe:
- Is climate stable?
- Is uptake normal?
- Is pH stable?
- Is drain EC trending or flat?
If any answer is “no”, fix that first.
Common mistakes to avoid
- Adjusting feed daily
- Treating symptoms instead of causes
- Ignoring climate and root-zone interactions
- Over-correcting micronutrients
- Forgetting stress memory
Key principle
Most crop problems are transport and environment problems, not formulation problems.
Fix function first — nutrition follows.