Root Rot From Overwatering on peace lily
What's Happening
Peace lilies (Spathiphyllum spp.) develop root rot from persistent overwatering that creates anaerobic soil conditions below 2mg/L oxygen threshold. When soil remains saturated for 7+ days, Pythium and Fusarium fungi colonize the fibrous root system, turning healthy white roots into black, mushy tissue that loses structural integrity and water uptake capability. The plant's tropical understory origin makes it vulnerable to waterlogging despite its dramatic drooping signal that owners often misinterpret as thirst rather than rot.
How to Fix It
- 1
Unpot the plant and gently rinse all soil from roots under lukewarm water to expose full root system
- 2
Inspect roots in bright light: healthy roots are firm and white/cream; rotting roots are black, soft, and mushy
- 3
Trim ALL blackened or mushy roots with sterilized shears, cutting back to firm white tissue
- 4
Treat remaining roots with 3% hydrogen peroxide solution (1:4 dilution with water) for 20-30 minutes to oxygenate and sterilize
- 5
Repot in fresh, sterile, well-draining aroid mix (50% peat/coir, 30% perlite, 20% orchid bark) in pot with drainage holes
- 6
Place in bright indirect light, 65-80°F, maintain >60% humidity; water sparingly until new growth emerges
What You'll Need
How to Prevent It
Water only when top 1-2 inches of soil are completely dry to the touch. Use well-draining potting mix amended with 30% perlite. Ensure pots have drainage holes and are never left standing in saucer water. Maintain 60-80% humidity to reduce water stress between waterings. Bottom-water only when necessary to control soil saturation levels.