Hydro Doctor
Answer a couple of quick questions about what you’re seeing to get a likely cause and a fix — for DWC, NFT, Kratky, drip, and aeroponic systems.
- Open formulas
- Runs 100% in-browser
- Peer-reviewed targets
- 1 System
- 2 Where
- 3 Symptom
- 4 Diagnosis
What are you growing in?
How the Hydro Doctor works
Four quick steps take you from symptom to a likely cause and a fix.
1. Pick your system
Optional — tell us whether you grow in DWC, NFT, Kratky, drip, or aeroponics so the diagnosis can be system-specific.
2. Choose where the problem shows
Leaves, roots, stems, the whole plant, or visible pests — each routes you to the matching set of checks.
3. Match the closest symptom
Select the description that best fits what you see. Everything runs 100% in your browser.
4. Get a diagnosis & fix
Review the likely cause, severity, and recommended fixes, then save or print the diagnosis.
Common hydroponic problems at a glance
The short version of the six issues growers ask about most. Use the checker above for a full walkthrough.
Why are the lower, older leaves on my hydroponic plant turning yellow?
This is usually nitrogen deficiency. Nitrogen is mobile in the plant, so it gets pulled from older leaves toward new growth first when the reservoir runs light. Check your EC/PPM against the target for your crop and growth stage, and confirm you haven’t been topping off with plain water only.
Why are the new leaves yellowing while the veins stay green?
That pattern (interveinal chlorosis) points to iron deficiency, and it’s almost always a pH problem rather than a lack of iron in the mix. Iron locks out above roughly pH 6.5. Test and correct pH into the 5.5-6.5 range and recheck in 24-48 hours.
What causes brown, slimy roots in DWC or hydroponics?
Root rot, most often Pythium, thrives in warm, low-oxygen, stagnant reservoir water. Trim affected roots with clean shears, boost aeration, keep the reservoir under about 72°F/22°C, and sanitize the system between crops.
Why do my leaf tips look brown and crispy?
That’s typically nutrient burn from an EC that’s too concentrated for the crop stage, or salt buildup after evaporation without top-offs. Dilute the reservoir toward your target EC and resume feeding at a lower strength.
What’s the white powdery coating on my leaves?
Powdery mildew, driven by high humidity, still air, and cool nights. Improve airflow and circulation, reduce humidity, remove affected leaves, and treat with an appropriate fungicide if it’s spreading.
Why did all my plants suddenly wilt at once?
In NFT and aeroponic systems especially, this is almost always a pump or power failure — roots have little to no reservoir to fall back on and can dry out within an hour. Check the pump, power, and timer immediately, and consider a float switch alarm or battery backup going forward.
Disclaimer: Hydro Doctor gives general guidance based on common hydroponic and aeroponic symptoms. For persistent or severe problems, cross-check with our in-depth guides or a local grower resource.