Q.Can A Moon Cactus Sustain On Top Of Very Small Base Rootstock?
I have a moon cactus whose base rootstock had 75% rot. So I removed the rotten part carefully and have planted it. Now my doubt is since base rootstock is very small, should I regraft cactus on to a new rootstock or is the remaining healthy part (which is very small) enough to sustain the cactus?

Certified GKH Gardening Expert
I would suggest regrafting. The top portion must get all its chlorophyll from the rootstalk and 25% may not be enough, plus it may continue rotting. Here is more:
https://www.gardeningknowhow.com/ornamental/cacti-succulents/moon-cactus/care-of-moon-cactus.htm
https://www.gardeningknowhow.com/ornamental/cacti-succulents/scgen/grafting-cactus-plants.htm