PlantRx

Pothos root rot

By Karim DiabatePublished Updated How these guides are built

Root rot on a pothos is a drainage problem before it is a disease. Roots sitting in mix that never dries suffocate first and rot second, so the fix is as much about what the plant is potted in as about the roots you cut away.

A healthy Pothos, photographed for reference
A healthy pothos for comparison. This is a reference photo, not a picture of the problem. Photo by Mokkie (CC BY-SA 3.0), via Wikimedia Commons.

What is specific to this plant

  • Pothos roots so readily in plain water that cutting back to clean stem and re-rooting the healthy pieces is often faster than nursing a rotted root ball back.
  • Fading variegation toward plain green is the earliest sign of too little light, and it shows up long before the plant looks unwell.
  • Long bare stretches of stem between leaves mean the vine is funding its growing tip at the expense of everything behind it.

What it could be, and how to tell

These look alike in a photograph, so each one below lists what you would ALSO see if that is the cause. Work down the list and stop at the one where the other symptoms match too.

most common

1. A root ball worth replacing rather than nursing

What else you would see

  • mush and blackened roots through most of the pot when lifted
  • stems still firm and green further along the vine
  • leaves collapsing faster than the plant can be dried out
  • a sour smell from the mix
How to confirm it: Judge the vines separately from the roots. A pothos roots from any node in plain water within weeks, faster and more reliably than a badly rotted root ball recovers, so the usual question of how to save the roots is the wrong one here. Firm green vine above a failed root system means the plant is easy to keep, just not in that pot.

What to do

  1. Cut the vines into lengths with a few nodes each, taking only firm green stem.
  2. Stand them in plain water until roots form, changing the water regularly.
  3. Pot the rooted pieces into fresh mix and discard the old root ball.
common

2. A mix that never dries out

What else you would see

  • mix still wet days after watering, when this much should have dried: the top two inches
  • a heavy pot, and a dense mix that has compacted down
  • a sour or musty smell from the surface
How to confirm it: Push a finger well into the mix a few days after watering. If it is still wet down there, the mix is the problem and no change in watering habit fixes it on its own.

What to do

  1. Take the plant out and remove all of the old medium.
  2. Cut back every root that is brown, soft or hollow, using a blade sterilised first, back to firm tissue.
  3. Repot into fresh free-draining potting mix, in a pot with real drainage, sized to the roots that remain rather than to the old pot.
  4. Water sparingly until new growth appears.
common

3. Several cuttings in one pot, one of them already rotting

What else you would see

  • six or eight separate stems coming straight out of the mix rather than one plant branching
  • one stem soft or blackened where it enters the mix while its neighbours are firm
  • vines failing one at a time over weeks rather than the whole pot going together
  • a sour smell at the surface with much of the plant still looking well
How to confirm it: Take hold of each stem at the mix and pull gently. A pothos sold as one plant is a handful of separate cuttings stuck into the same pot, each with its own small root system and none of them joined to the others, so one that has rotted sits in the middle of the pot against roots that are still sound. A stem that lifts out soft and blackened at the bottom has already gone and is the source rather than a casualty.

What to do

  1. Pull out every stem that is soft at the base and bin it rather than leaving it in the mix.
  2. Wash the mix off what is left, cut each stem back into firm green tissue, and keep the pieces that are sound.
  3. Root the healthy cuttings in water or fresh mix rather than nursing a root ball that has been sitting in rot, which is usually faster with this plant.
  4. Repot the survivors into a pot sized to what actually has roots, not to the pot they came in.
less common

4. Watering on a schedule instead of on the plant

What else you would see

  • a fixed weekly routine regardless of season or light
  • the mix never actually reaching the dryness this plant wants: the top two inches
  • the problem arriving in winter, when the plant is using far less water
How to confirm it: Check whether it has ever dried this far between waterings: the top two inches. In winter, in lower light, the gap between waterings should get noticeably longer, and a fixed schedule is what drowns plants that were fine all summer.

What to do

  1. Water on dryness rather than on a fixed day of the week, and this is how far it should dry: the top two inches.
  2. Expect the interval to stretch in winter and shorten in summer.
less common

5. Water standing under the pot

What else you would see

  • a decorative outer pot or cachepot with no drainage hole
  • a saucer that is rarely emptied
  • rot starting at the very base of the plant rather than at the root tips
How to confirm it: Lift the inner pot out of the outer one and look. Standing water there is one of the most common ways a houseplant is lost, and it is invisible until you check.

What to do

  1. Always let the pot drain fully, then tip out whatever collects underneath.
  2. Water in the morning so any excess has the day to drain and evaporate.
uncommon

6. A pot far bigger than the root ball

What else you would see

  • a recent move into a much larger pot
  • mix at the outside of the pot staying wet for weeks
  • the plant looking worse rather than better since it was repotted
How to confirm it: Mix with no roots in it holds water indefinitely, because nothing is drinking from it. A plant recently moved up two or three pot sizes is sitting in a reservoir.

What to do

  1. Repot back down to a pot only slightly larger than the root ball, in fresh free-draining potting mix.
  2. Go up one size at a time in future.

Common questions

Can a plant recover from root rot?

Often, if enough firm root remains and the mix is changed at the same time. Cutting rotted roots away while leaving the plant in the mix that caused it is the usual reason a rescue fails.

How far back should I cut?

Into clean firm tissue, every time. A root that is soft, brown or hollow is already gone, and anything left behind carries on rotting in the fresh mix.

Should I use a fungicide?

The reliable part of the fix is mechanical: remove the rotted tissue and the waterlogged medium, and repot into something that drains. If you choose to use any product, follow the instructions on its label exactly, since the label is the legal instruction and overrides anything written here.

Is a pothos poisonous to cats, dogs or children?

Pothos contains calcium oxalate crystals and is widely listed as harmful to pets and children if chewed. We do not tell you that any plant is safe. If a pet or a child may have chewed any part of one, contact a vet, or Poison Control on 1-800-222-1222 in the US, immediately rather than waiting to see what happens.

Before you act on any of this

This is general plant care guidance for a plant, not advice about people or animals. We never tell you whether a plant is safe to eat or touch, and we never tell you a plant is safe for a child or a pet. If a child or animal may have eaten any part of a plant, contact Poison Control (US 1-800-222-1222) or a vet immediately rather than reading further.

Treatment advice here is deliberately category level. We do not give product names, mixing ratios or application intervals. Whatever the label on the product in your hand says is the instruction that counts, and following it is your responsibility.

Where this comes from

The general horticultural facts behind this differential come from published university extension and Royal Horticultural Society guidance. What is specific to this plant, and the order the causes are ranked in, is ours, and the methodology page says where that reasoning stops being reliable.

Other pothos problems

Not sure which one it is?

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