Cactus decoloring and white-ish lines

Question

Cactus became to decolor recently, mostly near the roots (not the yellow-green parts, talking about white-green-ish parts). They are not mushy, or hard as all normal green parts. Also, on the over side of the cactus, there are same patches but with something like white lines (like stretch marks?). Was watering it once in a 1.5-2 weeks.

As these parts are still hard I believe it's not some kind of rot, but I may be wrong as I'm fairly new to cactus-things. Thoughts were that this is due to too much exposure to sunlight so I moved in a little further from the window, however, it didn't help. It was moved to a new pot recently via transshipment, roots were looking good. Smaller plants near it (seen in the pictures) are growing nicely, they were transferred together with the big one.

What could it be? Is it dying and requiring some more or less urgent action or it is not as bad?

Answer 1

Alex, props to you for dipping your toes into the wonderful world of cacti! We love our spiky buddies!

From what you've described...your cactus may be showing signs of something called 'corking'. This is where the cactus forms a sort of bark at its base. It happens as it ages.

It tends to look whitish or brownish and feels hard to the touch, like you said.

Corking often starts at the base and moves upwards. So that might be what you're seeing.

The white lines, are they kinda like stretch marks? If so, this could be due to rapid growth or a sudden change in conditions - like moving it to a new pot.

You seem to be taking good care of your cactus, watering it adequately without overdoing it. The smaller plants growing nicely is a good sign!

The best advice I can give is to keep an eye on it. If it starts to feel soft or look discolored elsewhere, that might be cause for concern. But for now, your cactus friend seems to be doing just fine. Keep doing what you're doing and don't hesitate to check in if anything changes.