Yikes!
Noticed this when checking plants today. 2 spots on my daughters fairy castle cactus. Doesn’t feel soft even where the dark spot is. This doesn’t get watered very often. I actually worry it gets underwatered sometimes. I am new to cacti. Is this an aging thing or a water issue? Thanks. #PlantAddict #PlantsMakePeopleHappy #SucculentLove #CactusClique #FairyCastleCactus #help
2ft to light, direct
5” pot with drainage
Last watered 1 day ago
5
could be an injury but that shade of brown looks like decay to me. We had a post recently on how to save a cactus from rot which basically involved cutting out the affected portion. If it was mine I would just leave it be since there is plenty of new and healthy growth. if it spreads it may be time to operate.