Q.White Coloured Fungus Like Substance On Rock Near Rock Plant
I have a rock plant “Mini Umbrella” (schefflera arboricola). On the rock near the plant, there’s white coloured powder like substance, look like growing. Is it fungus? How can I treat it? Thank you, Gk.

Certified GKH Gardening Expert
That looks to be Actinomycites. It is harmless to your plant, and is doing a good service to your soil.
It is a sign that the seedling is remaining far too moist for far too long, though. I would make sure that the young plant has time to dry out just to where there is barely any moisture in the substrate before watering again. Though the fungus will not harm your plant, the conditions for it to thrive means that it is unsuitable for your plants.
Here is an article that will explain what the fungus is, and its role in soil building:
https://www.gardeningknowhow.com/composting/manures/fungus-growing-on-manure.htm

The instructions that came with the plant said never let the rock dry, keep the water level top! Hence I may have over done that!!!! Also, being an indoor plant, this has never been in sunlight.