Root rot happens when soil stays wet so long that roots can't get air. The roots die and decay, and then the plant can't drink even though the soil is wet. It is the most common way indoor plants are lost.
Signs
- The plant wilts or yellows even though the soil is wet.
- Soil that smells sour or musty.
- Stems that are dark, soft or mushy near the soil.
- Stunted or no growth, and leaves that fall.
- The pot has no drainage hole, or water sits in the saucer.
How to check
Slide the plant gently out of its pot. Healthy roots are firm and pale (white, cream or light tan). Rotten roots are dark brown or black, soft or slimy, and may smell bad.
What to do
- Cut off every rotten root with clean scissors. Keep the firm ones.
- Remove as much of the old wet soil as you can.
- Repot in fresh, free-draining mix in a pot with drainage holes. Use a pot that is not much bigger than the roots.
- Water lightly once, then wait until the top of the soil is dry before watering again.
- Keep the plant in bright, indirect light and be patient. Recovery takes weeks.
- If most of the roots are gone, take stem cuttings from healthy growth to start again.
Prevention
Water only when the top layer of soil is dry. Always use a pot with drainage and empty the saucer.
When to scan
If you can't tell whether a stem is rotten, take a photo of the stem base and the whole plant in daylight and scan it.