Well, I've been trying to figure out what this strange white cotton, fungus looking thing is, it seems to be a part of the dirt maybe? and I've been looking at some posts but I don't know myself if this is a fungus or just deposits or something. I haven't touched it, planning not to, but I originally thought it might be mycelium since I left some dead, fallen off leaves in the pot. Any advice?

- 11
- 1
2 Answers
It looks as if the fungal growth is associated with debris on top of the soil, but it's also highly possible the soil itself is overly damp or wet. Whilst these plants might be thought of as needing little water, they should be watered thoroughly when the surface of the soil feels dry to the touch, with excess water being allowed to drain away freely from the holes in the pot. Excess water left sitting in a tray or outer container should be emptied out 30 minutes after watering to avoid the plant sitting in water.
If you are not watering correctly, adjust your method, and although the fungal growth is not lethal to you or the plant and requires no fungicidal treatment, as it's in the house, remove the debris from the top of the soil (wearing rubber gloves if you like) to reduce fungal spores. https://www.hortmag.com/weekly-tips/christmas-cactus-care-101

- 131,823
- 3
- 72
- 162
As suspected by you, this looks mycelium to me.
You could use Baking Soda to get rid of them.
ugaoo.com states
You’ll need one tablespoon of baking soda, mixed with a gallon of water and two and a half tablespoons of vegetable oil. Once the mixture is ready, add it to a spray bottle, shake the contents and spray the affected areas.
as one of the natural remedies to treat fungus. They also mentions few more other ways. Hope that helps.

- 240
- 1
- 8