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[dafritz]

I have been growing this San Pedro for a little over a year. After about 4 months is started to get black blisters and scaring. I assumed it was because of it being winter and it being stressed as the circumference of the cactus also got pretty narrow as well. However, it went all summer, and grew almost 2 feet during that time, but the scaring and blistering got worse. It is in a full sun southern facing window and I water it once every six to eight weeks or so. Humidity is between 40-55 depending on the month. Other than that it grows quickly and seems otherwise healthy. No pests, etc. Any thoughts on helping San Pedro out?

[Psylocke]

Cacti are better off taking a break during the winter. Even in a south facing window, it is unlikely to get enough light and it will etiliolate. Put her in a cool (below 60F) dark place for winter and give a little water no more than once a month. A mature plant will be fine for several months without water as long as temps are low and it doesn’t get much light.

As for the immediate problem, the black blisters will usually scar over and it will recover. If it gets worse, daconil will clear it right up. It’s a contact fungicide and won’t absorb into the plant. If you don’t want to go that route, just keep it dry (no watering) until it gets better.

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