Help, sunburn / rot / something else?

[degiorgi]

Hi, I am new to this forum, and to cacti in general.. My girlfriend bought some to me, and i think two of them might be sick. As for the first one, i think that might be sunburn? Or is it something else? It has kind of white/grey spots on one side near the top.. And for the second one, im not sure what it is.. Some grey / brown spots on the bottom

Any help?

[greenknight]

The first one does look sunburned. The second one, is that area soft? If not, there's no problem. If it's mushy, it's rot.

I'm a little concerned about the soil they're potted in, it look like it has too much peat in it, which would make it hold too much water. You might need to mix more grit into that, see the Cultivation forum for discussion of what makes good cactus soil (most commercial cactus soils aren't good).

[degiorgi]

Thanks for the answer. It's not mushy, on touch it's the same as the rest of the cactus. So i guess that's ok then?

About the soil, yeah this is just store bought "cactus soil". I'll check the cultivation forum, thanks!

[greenknight]

Yep, if it's not soft it's likely just normal corking - the base of columnar cacti gets woody with age, and that's a monstrose form of a columnar cactus. On globular cacti the old tissue shrinks up and disappears under the plant, that's how they stay the same shape while only the top part is growing - with them you can't see the corking unless you take the plant out of its pot.

[degiorgi]

Thanks a lot for the info!