Hydroponic Troubleshooting Guide 2026 | Fix Common Problems
Fix common hydroponic problems. Diagnose and solve nutrient deficiencies, pH issues, root rot, and algae in your growing systems.
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Take Our QuizPlants communicate through their leaves. Learning to read these signals transforms troubleshooting from guesswork into diagnosis. This guide covers the problems you'll actually encounter.
## Quick Diagnosis Chart
| Symptom | Most Likely Cause | First Check |
|---|---|---|
| Yellow older leaves | Nitrogen deficiency or pH | Check pH |
| Yellow younger leaves | Iron deficiency | Check pH (usually too high) |
| Brown leaf tips | Nutrient burn | Check EC/TDS |
| Brown/slimy roots | Root rot | Check water temp, oxygen |
| Wilting with wet roots | Root rot | Check roots directly |
| Slow growth | Low light or low nutrients | Check light hours, EC |
| Leggy/stretchy plants | Insufficient light | Add light or move closer |
| Algae in reservoir | Light reaching solution | Block all light |
The honest truth: 90% of problems trace back to pH. Always check pH first. It's the cause more often than you'd expect.
## Yellow Leaves
Older leaves yellowing (bottom first): Usually nitrogen deficiency. Fix: Check pH first (nitrogen lockout above pH 7). If pH is fine, increase nutrients.
Younger leaves yellowing with green veins: Iron deficiency. Almost always caused by high pH above 6.5. Fix: Lower pH to 5.5-6.0.
All leaves pale yellow-green: General nutrient deficiency. Check EC/TDS. If adequate, check pH. Fresh solution often resolves this.
## Root Problems
Brown, slimy roots: Root rot. Caused by pathogens in warm, low-oxygen water. Keep solution below 72°F (22°C). Add more aeration. Consider beneficial bacteria like Hydroguard (widely available at US hydro shops and Amazon).
Brown but firm roots: Nutrient staining. Cosmetic, not harmful.
## The Diagnostic Process
1. Check pH (it's almost always pH) 2. Check EC/TDS 3. Check water temperature 4. Check roots directly 5. Check light levels 6. Check for pests
This order catches 95% of problems. Work through systematically rather than guessing.
For step 1, our pH guide has everything you need. For understanding nutrient targets, the [nutrients roundup](/guides/best-hydroponic-nutrients-us) explains EC targets and what to buy.
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