pests and diseases
Root rot
Last reviewed 2026-10-04
Root rot is the decay of plant roots. It is often associated with saturated soil, poor drainage, low oxygen, or organisms that damage weakened roots. Symptoms may include wilting despite wet soil, yellowing, slow growth, leaf drop, or dark and soft roots. Symptoms overlap with other problems, so inspect the root zone when possible.
What it means
Healthy roots usually have a firm texture appropriate to the plant and a functioning connection to the stem. Rotting roots may be brown, black, soft, or easily separated. Some organisms remain in soil or containers, while other cases begin with waterlogging and root injury.
How it affects the garden
Correct the moisture and drainage problem before watering more. Remove damaged roots and repot affected containers into a clean, suitable medium when the plant and condition allow. Avoid reusing contaminated mix. In garden beds, improve structure and choose plants that match the moisture pattern rather than creating a permanently wet root zone.
The potting mix calculator estimates new mix volume, while the soil calculator estimates bed material. Neither diagnoses a pathogen.
Example
A houseplant stays wet in a pot without an open drainage hole and begins wilting. Checking the roots reveals decay, so the gardener addresses the container and moisture conditions instead of adding more water.
Common confusion
Root rot is not the same as a root-bound plant. A root-bound plant has limited space, while root rot is damaged or decaying tissue.
Sources
University of Minnesota Extension explains overwatering, poor drainage, and root damage in houseplants.
