My grandpa has a cactus that is turning almost metallic gray. It appears to start low but doesn't seem like obvious rot. The effected area is not mushy. It has quite a bit of new growth on the top over the past month or so. The plant is in the patio window and the discoloration does not show up on the side facing the sun. We live in WI but despite winter he keeps the house at 70°. I dont believe there is a draft but they are right next to the heater vent and have been in the same spot for years. He waters them once a week, when I am there the soil seems very dry. The soil is old and we are planning on re-potting. I am wondering if there is something we should do differently when re-potting? Or if there is something we should be looking for, besides usual signs of rot? Is it putting all its energy into new growth? Is this the result of not having enough room to grow? Didn't think this made sense but I am not sure exactly what the problem is. It's my grandma's cactus and keeping it alive or salvaging what we can is very important so any advice is appreciated.
@Amnorton4 I’m a new member and wondering if you’ve received a reply about your cacti turning metallic gray with new growth thriving on top. You described the problem I’m having exactly. Any help from you is greatly appreciated. Stay well
Pretty sure that is a Euphorbia, not a true cactus. I think the hint that it isn't discolouring where the sun hits it suggests it is a light issue--plants can compartmentalize, and if a part of the plant isn't doing its part due to lower light conditions, it can shut down / vacate / not invest in chlorophyll production in that area, which I suspect is happening. What is your light situation like, @Socrates?
