I brought a cactus home from work thinking he would like a little sun. After a few days I found him turning white. My other cacti are happy. Too much water? How do I save him?
Was it placed behind glass or not in your home? I does not look like overwatering, more like an etioliated cactus, grown indoors in poor light, that was placed in direct sunlight and got scorched, especially the uppermost, etioliated growth with the lowest sun tolerance.
I put it out on my deck with my other plants. It had been in a a coffee shop away from Windows before. Will it survive? Can I do anything for it now? It is now indoors and gets 2-3 hours of morning sun.
The scorched part isn't going to unscorch, but I would guess the rest would still be ok. I would put it outside in the shade for a few days, then give it gradually more and more sun. If it can't grow from the top, it should put out new growth from someplace else on the plant. I'd expect the problem to be more the etoliated top growth - would you want new growth there anyway? How would it support it? Would it be better to take that off? Sorry - I have only questions. It sounds like @mandarin knows more about these things.
Yes, let it get used to the sun gradually, treat it like a fair-skinned human. The sensitivity to ultraviolet light varies a lot from species to species, some become sunburnt very easily, others seem nearly impervious. I think it is best to cut off the top, even if the growing point has survived it will not grow into anything useful to the plant. Do not turn the plant once it has got accustomed to the sun, only the areas exposed to the light will get "tanned".
