Root Rot
Root rot is the houseplant emergency: roots suffocate in waterlogged soil, die, and are colonized by fungi that spread to healthy tissue. Above the soil the plant wilts and yellows -- which tempts many owners to water more, accelerating the decline. Caught early, most plants can be saved.
Quick Diagnosis
Wilting despite wet soil is the classic tell. Confirm by unpotting: healthy roots are firm and white to tan; rotted roots are brown or black, mushy, and may slide apart or smell sour. Yellowing lower leaves, a soggy stem base, and soil that stays wet a week or more after watering all support the diagnosis.
Causes
Understanding the root cause is the first step to fixing the problem.
- 1Chronic overwatering keeping the soil saturated and airless.
- 2Pots without drainage holes, or decorative cache pots collecting hidden standing water.
- 3Dense, compacted soil that stays wet for weeks.
- 4A pot far too large for the plant, holding more wet soil than the roots can use.
- 5Fungal pathogens (Pythium, Phytophthora, Fusarium) attacking roots weakened by wet conditions.
- 6Cool temperatures slowing evaporation and root activity in winter.
Treatment Steps
Follow these steps to treat root rot in your indoor plants.
- 1
Unpot the plant immediately and wash the soil off the roots.
- 2
Trim every mushy, discolored root with sterilized scissors, cutting back to firm tissue. Sterilize between cuts on badly rotted plants.
- 3
Optionally soak remaining roots in a 1:2 solution of 3% hydrogen peroxide and water for a few minutes.
- 4
Discard the old soil, wash the pot with hot soapy water, and repot in fresh, fast-draining mix.
- 5
Cut back some foliage to match the reduced root system -- a plant that lost half its roots cannot support all its leaves.
- 6
Water lightly and place in bright indirect light. Do not fertilize until vigorous new growth appears.
- 7
If the rot reached the stem, take healthy cuttings as a backup before attempting the rescue.
Prevention Tips
Keep your plants healthy by following these preventive measures.
- Always use pots with drainage holes, and empty saucers and cache pots after watering.
- Check soil moisture with a finger before every watering -- water the plant, not the calendar.
- Use airy mixes with perlite or bark matched to the plant type.
- Size pots just 1-2 inches wider than the root ball.
- Cut watering frequency significantly in winter.