Root Rot: Signs, Causes & How to Save Your Plant

Quick Answer

Root rot is caused by overwatering and poor drainage. Roots turn black and mushy, can't absorb water or nutrients. Act fast: unpot, trim rotted roots, treat with hydrogen peroxide, repot in fresh well-draining soil, reduce watering.

Root rot often looks like other problems, but these signs together indicate root issues:

• Yellowing or wilting leaves despite wet soil
• Soft, mushy stems at soil level
• Foul, rotten smell from soil
• Soil stays soggy for days after watering
• Black or brown mushy roots (when you unpot)
• Plant doesn't perk up after watering—actually gets worse
• Mold or fungus gnats around soil

1. Overwatering (Primary Cause)

   Keeping soil constantly wet deprives roots of oxygen. Roots suffocate and die, then fungal/bacterial pathogens attack the dead tissue, causing rot.

2. Poor Drainage

   Heavy, dense soil (like garden soil) or soil that's broken down and compacted retains too much water. Water pools instead of draining through.

3. No Drainage Holes

   Pots without drainage holes trap water at the bottom. Even careful watering leads to waterlogged roots eventually.

4. Pot Too Large

   Oversized pot holds more soil than roots can use. Excess soil stays wet and invites rot.

5. Cold Temperatures

   Cold soil (below 60°F / 15°C) slows root activity and drainage. Wet + cold = perfect rot conditions.

What to Do

1. Unpot and Inspect Roots

   Carefully remove plant from pot. Healthy roots are white or tan and firm. Rotted roots are black, brown, mushy, and may smell bad. Shake off old soil gently.

2. Trim All Rotted Roots

   Use clean, sharp scissors or pruners. Cut away ALL black/mushy roots until you only see healthy white/tan roots. Be aggressive—rotted sections won't recover.

3. Treat with Hydrogen Peroxide (Optional)

   Mix 1 part 3% hydrogen peroxide with 2 parts water. Soak remaining healthy roots for 5-10 minutes to kill pathogens. This step helps prevent rot from spreading.

4. Repot in Fresh Well-Draining Soil

   Use new potting mix (never reuse old soil—it's contaminated). Choose a mix with perlite, bark, or sand for drainage. Pot should be just big enough for remaining roots.

5. Adjust Watering Going Forward

   Water only when top 2-3 inches of soil are dry. Use the 'soak and dry' method: water thoroughly until it runs out drainage holes, then let soil dry before watering again.

6. Monitor for Recovery

   Plant may look worse for 1-2 weeks (shock from root loss). If you see new growth after 2-3 weeks, recovery is underway. Keep humidity high to help.

• Always use pots with drainage holes—no exceptions
• Use well-draining potting mix (with perlite, bark, or sand)
• Water only when soil is dry 2-3 inches down (stick your finger in)
• Empty saucers/cachepots 15 minutes after watering
• Choose pot size that's only 1-2 inches larger than root ball
• Keep plants in warm locations (above 60°F / 15°C)