Root rot
The plant wilts while the soil is wet, the lower leaves turn yellow and the stem base goes soft. The roots are brown, mushy and smell musty; healthy roots are white and firm.
Soil-borne organisms such as Pythium and Phytophthora attack roots that sit in wet, airless soil for too long.
What can you do?
- Take a houseplant or pot plant out of its pot and cut off all brown, soft roots with clean scissors.
- Repot in fresh, open compost in a clean pot with a drainage hole and water sparingly afterwards.
- Throw away badly affected plants with their compost, not on the compost heap.
- In the garden: dig out dead plants with their roots and improve drainage before replanting, for example where conifers or yew are dying.
Prevention
Don’t overwater, use pots with a drainage hole and in the garden plant only species suited to wet or heavy soil.
When to watch out: October–March