Hey All. I’ve owned this cactus for about a year. It’s been kept indoors all its life and just recently started showing these signs. What’s going on here? The spots have come and go but just recently have begun to grow and flake. The blackening on the tip of the pup is only about 2 weeks old. I googled it and found that a plethora of things can cause this. I have two living out doors that are growing beautifully. Should I move this one outside? Will that shock it going from room temp to 100°+ Texas temps? Let me know how I should go about this. I’m a total newb when it comes to San Pedro so go easy on me if I’m doing it all wrong. Thanks in advance for the help!
by OfferInternational15
5 Comments
First order of business is dig up at cactus and check out the roots. Make sure you’re not rotting there.
cut top from the pup, it could be they’re so cus high humidity and overwatering, put them outside.
Looks like two different things to me. You’ll want to remove the black on the pup asap no matter what caused it, that will only spread. Then I’d treat the fresh cut with a sulfur dusting and hope for the best. The scaley spots, assuming they’re hard, looks like a fungus. Harmless to the cactus but unpleasant for the aesthetic. Just my take, not an expert.
That is a fungus of some sort causing the spots in the second pic (concentric circles with a black center is a dead giveaway). The first pic looks like run of the mill rot, but it could also be the result of the fungus.
I would: chop an inch or two below the rot on the pup (or just cut off the whole thing), put sulfur on the wound, and spray copper octanoate fungicide on the affected areas. Try to keep it out of the soil, because too much copper in the soil can have bad effects on the root health and microbiome of the soil
This thing wants more light, and less water while it’s indoors. Even with a significant amount of indoor grow lights my cactuses exploded with growth once I started putting them outside for the summer. Yes, you need to transition them carefully with gradually more exposure, but they will thank you for it. I grow in NM and during the summer I can water them every 1-2 days and they stay plump, happy and grow more in a few months than they have in years indoors.