How to tell if your plant has root rot

Plant problems · Updated August 5, 2026 · 3 min read

Short answer

The most reliable above-ground sign is a contradiction: the plant wilting while the soil is wet. Confirmation only comes from lifting the plant out — healthy roots are firm and pale, rotten roots are brown-black, soft, and their outer sheath slips off when squeezed.

On this page

Signs above the soil
Confirming it: look at the roots
Treatment
Preventing it
When to stop trying

Root rot is not one disease. It is what happens when roots run out of oxygen: in permanently wet soil root cells suffocate, die, and the dead tissue opens the door to fungi that were already in the pot. Which means the cause is almost never watering itself — it is drainage.

Signs above the soil

None is conclusive alone; together they are.

The reliable one: wet soil, wilting plant. Dead roots cannot move water, so the plant behaves as if it is thirsty. Its owner usually waters it, which speeds everything up.
Leaves yellowing, starting from the bottom.
Growth stopped; no new leaves, or small ones.
The stem soft where it meets the soil, and darker than it was.
A sour, boggy smell from the pot.
Soil still wet days after watering.

Confirming it: look at the roots

Do not guess. Lifting a plant out does not hurt it.

Tip the pot sideways and ease the plant out by the base of the stem.
Crumble away the outer soil by hand.
Rinse the roots in lukewarm water.

	Healthy root	Rotten root
Colour	White, cream, light tan	Dark brown, black
Texture	Firm, springy	Soft, waterlogged
When squeezed	Resists	Sheath slips off, thread remains
Smell	Like soil	Sour, boggy

Treatment

If less than a third of the root mass is rotten, the odds are good. More than half gone means poor odds, but it is still worth trying.

Cut. With alcohol-wiped scissors, remove every rotten root back to sound tissue. When in doubt, cut — rot left behind keeps spreading.
Rinse what remains under running water.
Fresh soil. Throw the old mix away; it carries pathogens. A standard houseplant mix with a third perlite drains well enough for most plants.
Size down the pot. With less root mass, the old pot is now too big, and excess soil holds water — which is how this started.
Reduce the foliage. If there are more leaves than the remaining roots can supply, remove some of the oldest.
Water sparingly and do not feed. Damaged roots cannot process fertiliser; it only adds salt.

Preventing it

Use pots with drainage holes. A pot without one is the shortest route to root rot.
Empty the cachepot 15 minutes after watering.
Check before watering. If the top 3–5 cm is not dry, waiting is always safer.
Go up one pot size, not two. In an oversized pot the soil the roots do not reach stays wet for weeks.
Water less in winter. Growth slows and water use drops; keeping the summer rhythm is the classic winter mistake.

When to stop trying

If the stem has gone soft and brown where it meets the soil, the rot has moved up out of the roots and the odds are very low. If the top of the plant is still sound, take a cutting — that is the realistic rescue: cut a healthy shoot and root it in water or damp mix.

Frequently asked questions

Is root rot contagious?

It does not spread through the air, but the organisms travel in soil and water. Sharing soil, watering cans and unsterilised scissors raises the risk. Always wipe scissors with alcohol after cutting rotten roots.

Do cinnamon or charcoal stop root rot?

Both can help dry a cut surface and slow surface fungal growth, but neither treats established rot. The treatment is removing dead tissue and fixing drainage.

When can I fertilise again?

Once new leaves or shoots appear — usually four to eight weeks. Feeding earlier burdens a damaged root system rather than helping it.

Does growing in water prevent root rot?

Roots grown in water develop differently and cope with it. Moving a soil-grown plant into water is risky in itself, because its roots have to adapt, and the water needs changing weekly.