Q.My night blooming cereus has a powdery white substance on it. Is it from over watering ?
This plant was a gift 3 years ago. It has really taking off as far as growing and has had 2 beautiful blooms. I just don’t know how to properly take care of it….pruning, feeding, etc and of course, the white powdery substance. A lot of it rubs right off, but not all of it

Certified GKH Gardening Expert
There are many things that will kill powdery mildew. This one will be easy to get rid of. The easiest way will be peroxide. Mix it at 1/4 strength into water, and spray this onto the plant and into the epiphyte soil that it should have come in. This will kill off the mold, and spores.
As far as care... This article will help: https://www.gardeningknowhow.com/ornamental/cacti-succulents/night-blooming-cereus/night-blooming-cereus.htm