Plant care guide
Mold on Pothos Soil: What It Means and How to Stop It
Updated · First published
Why does my Pothos have mold?
White or grey fuzz on pothos potting mix is usually a fungus feeding on the organic matter in the mix, not on the plant. It isn't usually harmful, but it shows the surface is staying wet. That same wetness favours fungus gnats and root rot.
What to do first
Scrape off the fuzz and the top layer of mix. Let the mix dry between waterings, empty the saucer, and give the plant more light and airflow. If mold keeps returning, check the drainage, the pot size and the roots.
Fuzzy growth on your pothos soil looks worrying, but the plant itself is rarely under attack. The fuzz is a fungus living on the organic matter in the mix. Treat it as a sign that the mix is staying wet for too long.
University of Maryland Extension’s page on algae and fungal growth describes fungi forming a white to greyish layer on moist potting mix. It says this growth isn’t usually harmful to plants.
Identify what is on the mix
| What you see | Most likely |
|---|---|
| White, grey or yellowish fuzz or threads | Fungal growth (mycelium) |
| Green film on a wet surface | Algae |
| Small mushrooms | A mushroom-forming fungus |
| White to grey crust on the surface or rim | Salt buildup |
| Hard white grains mixed through the pot | Perlite |
UF/IFAS Extension’s guide to mushrooms in potted plants explains that many of these fungi feed on decomposing organic matter such as bark and moss. They are not necessarily harmful to the plant. Clemson Extension’s houseplant disorders factsheet describes white to grey crusty deposits as a sign of salt buildup, not mold. Virginia Cooperative Extension’s watering guide describes perlite as the small white particles in potting soil.
When it matters. UMD and UF both warn that a thick fungal mat can stop water soaking in. UMD adds that the mat can attract fungus gnats and shore flies, whose larvae feed on roots.
Mushrooms. UF says the yellow Leucocoprinus birnbaumii is the most common mushroom in indoor potting soil and is considered poisonous. Touching it is safe, but pick it out if children or pets could reach it. Never eat an unknown fungus.
Remove the growth and reset the surface
- Break up or remove the mat. UMD advises stirring it with a fork or removing the top layer of mix with it.
- Clean up. Pick dead leaves off the surface and wipe the pot rim and saucer.
- Let the mix dry before watering again. NC State Extension’s pothos profile advises letting the well-drained mix dry out between waterings. UMD recommends letting the surface dry to stop the growth returning.
- Improve light. UF links fungal growth in pots to high humidity, low light and warm temperatures. NC State says pothos prefers bright, indirect light.
- Improve airflow. UMD advises good air circulation between pots.
Hold off on fungicides. UF recommends asking your local Extension office before applying any, and says chemical products should always come with changes in care.
If the mold keeps coming back
Recurring growth means the mix is still too wet. Iowa State University Extension’s guide to environmental problems lists the usual reasons a pot stays wet:
- watering too often
- no drainage hole
- a saucer or outer pot holding water
- old mix that has broken down and holds less air
- a pot too large for the roots
Fix whichever applies. Iowa State recommends repotting into fresh, well-drained soil when old mix has compacted. Our pothos repotting guide covers the steps.
Rule out root rot and gnats
Surface fungus and root rot are separate problems, but both follow wet mix. NC State notes that overwatering can cause root rot and blackened leaf margins on pothos. Virginia Cooperative Extension lists other overwatering signs: yellowing on new and old leaves, mushy stems, rotten-smelling mix and fungus gnats.
If you see those, slide the plant out and check the roots. Our pothos root rot guide and overwatering guide walk through the rescue. If small dark flies hover around the pot, see the pothos fungus gnat guide.
Water so the surface can dry
Water thoroughly, then let the pot drain. Virginia Cooperative Extension says overwatering is about how often you water, not how much. Do not leave the pot standing in a saucer for more than 60 minutes.
Check the mix before each watering instead of following a calendar. For more on fungus in pots, read mold on houseplant soil. The pothos care guide covers the full routine.
References
- University of Maryland Extension: Algae and Fungal Growth on the Soil of Indoor Plants
- UF/IFAS Extension: A Basic Guide to Mushrooms Commonly Encountered in Potted Plants in Florida (PP377)
- NC State Extension Gardener Plant Toolbox: Epipremnum aureum
- Iowa State University Extension: Diagnosing Houseplant Problems from Improper Environmental Conditions
- Virginia Cooperative Extension: Properly Watering Container Houseplants (SPES-804)
- Clemson Cooperative Extension, HGIC 2251: Houseplant Diseases & Disorders
How this guide was put together: University of Maryland Extension, UF/IFAS Extension, NC State Extension, Iowa State University Extension, Virginia Cooperative Extension and Clemson Extension guidance.