Root Rot: Brown Slimy Roots and How to Save the Plant
By The Budometry TeamPublished Updated
Healthy roots are white and smell faintly earthy. Brown, slimy roots that smell sour mean the root zone ran out of oxygen and opportunistic pathogens moved in.
Part of our pillar guide: Plant Training, Pests and Troubleshooting
Above-ground symptoms
Wilting that does not respond to watering, yellowing that spreads fast across the whole plant, and stalled growth. Growers often mistake it for a nutrient deficiency and feed more, which accelerates the decline.
In soil
Stop watering. Let the pot dry back substantially. Improve drainage and airflow beneath the pot — a riser or a fabric pot on a rack helps enormously. Add beneficial microbes on the next watering.
In hydro
Get reservoir temperature below 68°F, increase aeration, and clean the system. Warm water holds far less dissolved oxygen, which is why most DWC root rot happens in summer.
Prevention
Fabric pots, proper wet-dry cycles, a well-draining medium with perlite, and cool reservoirs. Root rot is nearly always preventable.
Frequently asked questions
- Can a plant fully recover from root rot?
- If caught early, yes — new white roots appear within a week. Advanced cases rarely produce a decent harvest.
The full guide on this topic
Plant Training, Pests and Troubleshooting
Topping, LST and SCROG explained, plus how to identify and stop spider mites, fungus gnats and powdery mildew, and how to read leaf symptoms correctly.