White mold on the base of a grape ivy (Cissus alata, previously C. rhombifolia). Picture: matusskaaaaa, depositphotos
By Larry Hodgson
Reading: White mold growing on potting soil
Once you backyard indoors lengthy sufficient, you ultimately run into this case. White mold seems on the floor of the soil of a houseplant or maybe some seedlings. What’s it? And is it dangerous? And the way do you do away with it?
Table of Contents
What It Is
The mold is a kind of filamentous fungus. (I can’t be extra exact than that, as there are dozens if not lots of of species that each one look just about alike.) Such fungi are ever-present in our surroundings: their spores float round within the air each indoors and out and germinate once they discover a substrate that fits them. And spores could also be current within the potting soil you purchase. Or may need been current within the greenhouse the place the plant was bought. Or carried on a potting instrument. Or your fingers …
What can I say? Fungus spores are in all places!

This type of fungus is saprophytic: it lives off decomposing particles of natural matter (wooden, peat, leaf mold, and many others.) discovered within the potting combine. It isn’t pathogenic or immediately dangerous your crops … neither is it dangerous to folks or pets. Actually, it really helps your crops, because the natural matter it digests incorporates minerals which might be then freed up. Your crops can subsequently take in and use them for his or her development.
In different phrases, white mold is a part of the composting course of, however composting in a pot quite than in a bin!
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The gradual decomposition of potting soil resulting from varied soil organisms (most invisible to the attention) is simply a part of the circle of life and normally goes on unnoticed. The looks of white mold is likely one of the uncommon examples the place you possibly can see Mom Nature at work.
The right way to Get Rid of White Mold
So, white mold on potting soil is regular and even helpful to a sure diploma, however you continue to in all probability don’t need it. First, for esthetic causes, maybe. Nonetheless, some sorts kind a community of mycelium so dense that it impedes air and water circulation to the plant’s roots and also you actually don’t need that. In both case, it’s greatest to take away it.
Merely take a fork and scrape off the higher floor of potting soil (it may go into compost pile and even immediately into the backyard) to a depth of about 1 inch (2 cm), then change with contemporary soil. That’s normally sufficient.
If ever it comes again (that’s pretty uncommon, however some species are extra persistent than others), you could must repot the plant, eradicating the previous potting combine and replanting it in contemporary soil in a clear pot.
Prevention
Decomposition goes on in all potting soils, however normally sight unseen. The presence of mold is normally associated to extra humidity, poor drainage or poor air circulation: issues you may appropriate. The present resurgence on the market of pots with out drainage holes is one motive the presence of white mold is extra widespread than in years previous.
Listed here are some strategies for stopping mold on potting spoil:
1. Let the soil dry out between waterings
Only a bit for seedlings, cuttings and most houseplants; extra deeply for succulents and different arid local weather crops.
2. Improve air circulation
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You can have a fan working within the room, for instance, or crack open a window.
3. Keep away from dense, heavy soils
Soils from the backyard, notably. Gentle, well-aerated potting soils, extensively out there commercially, are higher decisions.
4. Take away fallen leaves or different particles
They could be a supply of fungi or assist nourish fungi.
5. Replant crops growing in pots with out drainage holes into extra acceptable containers
What can I say? Growing crops in pots with out drainage holes is just a nasty gardening observe and could be dangerous to crops in so some ways!

6. Give your crops extra gentle
That manner, they’ll use water extra quickly and the potting combine will dry out extra rapidly, one thing mold fungi don’t like.
7. Take away mulch
Mulch is normally good for crops, however in conditions the place poor air circulation, excessive humidity or poor drainage prevail, it may stimulate fungal development. Or use chopped sphagnum moss as mulch: it has pure antifungal properties.
8. Apply a fungicide
I point out this as a final resort, as I really feel it actually shouldn’t be essential to “pull out the big guns” for such a minor drawback. Nonetheless, sure, business fungicides will assist stop mold or gradual its development, as will home-made merchandise like powdered cinnamon sprinkled over the soil or chamomile tea watered into it.
White mold on houseplant soil: it’s solely a minor drawback and it’s normally one which’s very straightforward to repair.
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