Overwatering and root rot: signs, causes and what to do

Root rot happens when soil stays wet for so long that the roots run out of air and start to decay, and overwatering is the most common cause in houseplants. A plant with root rot droops or yellows even though the soil is wet; start by letting the soil dry, then cut away soft roots and repot.

What does it look like?

Leaves yellow and droop even though the soil is wet.
Soil that stays damp for a week or more, or smells sour.
Stems soft and dark near the soil line.
Fungus gnats flying around the pot.

Why does it happen?

Watering on a schedule instead of when the soil has dried.
A pot without drainage holes, or a cover pot that holds water.
Heavy, compacted soil, or a pot much bigger than the roots.
Low light, so the plant uses water slowly.

What can you do about it?

Stop watering until the top few centimetres of soil are dry.
Slide the plant out of its pot and look at the roots. Healthy roots are firm and pale; rotten roots are brown or black, soft and may smell.
If some roots are rotten, cut them off with clean scissors and repot into fresh, well-draining mix in a pot with drainage holes, only slightly bigger than the roots.
Water lightly after repotting, then only when the soil has dried.
Give the plant more light so it uses water faster.

When you photograph a plant with this problem, Leafsight gives an assessment that names the likely problem, how serious it looks and how sure it is. Your first assessment that finds a problem includes care steps like these; with Pro or a one-time unlock, every one does.

When should you look closer?

Most of the roots are soft and dark: the plant may not recover, and a healthy cutting can be a backup.
The base of the stem is mushy: take cuttings from healthy growth if the plant allows it.

Questions

How do I know if my plant has root rot?

Root rot shows above the soil as yellowing, drooping leaves even though the soil is wet, and sometimes a soft, dark stem at the soil line or a sour smell. The only way to be sure is to look at the roots. Slide the plant out of its pot: healthy roots are firm and pale, while rotten roots are brown or black, soft, and may come apart when touched.

Can a plant recover from root rot?

It depends on how much of the root system is still healthy. If some roots are firm and pale, cutting off the rotten ones and repotting into fresh, well-draining mix gives a plant with root rot a chance, though it may lose leaves while it grows new roots. If most roots are soft and dark, or the base of the stem is mushy, a cutting from healthy growth is a sensible backup.

How often should I water to avoid overwatering?

There is no fixed schedule, because how fast soil dries depends on light, temperature, pot size and the plant. Overwatering usually comes from watering by the calendar. Instead, push a finger a few centimetres into the soil and water only when that depth feels dry, then water thoroughly and let the excess drain away. In winter and in low light, expect to water less often.

Should I repot an overwatered plant?

Not always. If the roots are firm and pale, letting the soil dry out and watering less often is usually enough for an overwatered plant. Repot when the soil stays soggy for a week or more, smells sour, or the roots show signs of rot. Use fresh, well-draining mix and a pot with drainage holes that is only slightly bigger than the roots, then water lightly.

Can root rot spread to my other plants?

Root rot starts from soil that stays wet in that pot, so a healthy plant beside it isn't at risk as long as its own soil drains and dries between waterings. The organisms involved can survive in old potting mix and on used pots, so repot into fresh mix and a cleaned pot, and don't reuse the old soil for another plant.

Not sure? Check with a photo

Leafsight looks at a photo of the leaf, asks a few questions about light, watering and drainage, and gives an assessment of the likely problem with care steps. A photo assessment can be wrong: for a hands-on look, ask a local garden centre or plant clinic.

Sources

Updated 2026-11-04. All plant problems.

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