How can I discourage mycelium and other fungi growth in my plant containers? And yes, is it even a good idea?

3 Answers 3


It's not something you should worry about - there's no way of getting rid of mycelium without using completely sterile soil. Even if you did that, the air is full of fungal spores and they may arrive anyway. All you can do is not overwater and ensure good drainage by not using pots without holes, etc,to discourage invasion by less friendly forms of fungi. In some cases, there is a beneficial or even symbiotic relationship between certain fungal mycelium and plant roots.

Under 'other fungi growth', you might be including fungal growths and infections which have aerial forms, like the mildews, black spot, rust, some varieties of phytopthera infection, but these do not produce mycelium in the soil, so I'm not sure whether you're including those in your question or not. Most are encouraged by warm, humid or damp, still air and insufficient air flow round plants; powdery mildew is often encouraged by dryness at the roots.


This is WHY potting soil is sterilized! Did you try to sterilize any of the soil you made? Shoot, there are some fungal and bacteria colonies you should embrace. Such as Mycorrhize! Especially if you are dealing with unknown garden soils/amendments in pots!!

You should have FANS going 24/7 for indoor plants especially those in crappy garden soil that hasn't been sterilized. This is one of the best preventative measures for fungus. Knowledgeable pruning and bio fungicides applied early on susceptible plants are two other measures to understand. Fungicides are primarily a preventative sort of a 'raincoat' for plants. There are fungicides for ornamental plants and a few for vegetables. Milk and water seems to be very effective for powdery mildew. Any other fungus needs preventative measures such as aeration pruning, fans, 'raincoats', not allowing water to splash up on plants (containing fungal spores galore), shielding from rain (get ready for powdery mildew, it is the lack of 'free water' or physical rain, water on the leaves, humidity/dryness such as under eaves of homes where rain is unable to reach that promotes powdery mildew as well as a plant's natural susceptibility).

  • I didn't. I was told that the soil is already sterilized. But maybe the garden soil I mixed wasn't sterilized, and that's where the problem arise. Well, I have used same proportion and same soil in 5 pots. The Mycelium is only growing in one pot. I will put more sterilized soil on top of the soil to cover it.
    – 4-K
    Commented Oct 23, 2016 at 13:19

I also wondered about this at some point, because a potted plant I had died of damping off.

I've since incorporated cinnamon into a potting mix I used into an homemade self-watering pot. I thought some antifungal was a good idea in a constantly moist soil.

Maybe my reasoning was wrong, and there is no increased chance of fungus developing in my self-watering pots, but the facts are that I've had no problem whatsoever in the last 6 months, and cinnamon might have been the key. I also read chamomile tea could be used similarly to avoid damping off.

  • 1
    Sounds like your 'self watering pots' aren't doing their job! Would it be a hassle to just water when you see and feel the soil is dry and they need more water? There is usually plenty of water below the surface and no plant should ever be watered on some human schedule. Learn the HEFT of a plant in its pot when watered and when it is dry. The difference is dramatic. Unless you are gone for weeks/months, water by hand. Any plant in a pot is completely dependent on its STEWARD. Completely. To allow a 'self watering' anything is asking for problems. Don't do cinnamon, or chamomile...
    – stormy
    Commented Oct 24, 2016 at 20:49
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    Maybe "moist" was too strong to describe the humidity of the pot. My point was that while the top of the potting mix is dry to the touch, I expect the bottom to be in a constantly humid state, and I feared damping off as a result. I use those because I am frequently gone for 1 or 2 weeks, and as a result I only have plants that can survive not being watered during that time, and plants in self-watering pots with a reserve that can usually last 2 weeks.
    – A.N.
    Commented Oct 25, 2016 at 10:40

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