Help me save this poor cactus please!

weezyking666eDluiwl0

Hello! Before I start describing the problem, I want to say that I don't know much about plants and I never did gardening as a hobby. I have plants in my apartment and I like them, but I don't know absolutely nothing about them and that's why I need your help to save my cactus! I just need an advice or just tell me it will die, at least I will know the truth.

So I found this cactus outside few months ago and thought to bring it home and give it a second chance, I bought a new pot and everything was good but I think there is something wrong with it.
I noticed that the yellow/brown spot which starts from the top it's becoming bigger and bigger (when I put it in the new pot, after some time it already had a brown top, I thought it felt bad after the stress of being found, re potted.... so I cut it off, but it won't stop)
Is there any possibilities to save it? I am not even watering it because I was scared it will completely die! 

I read on the net that it could be an infection or something, that it's rotting
Please help me, I want it to live!

KT53

It does appear to be rotting from the top and bottom so I doubt there's much you can do to save it.  I would cut my losses, bin it, and get another one.  Cacti need to be watered sparingly.

Buzzy2

The pot is to large.

clarke.brunt

I don't think that anything you could 'do to it' at this stage is going to help. If you want to keep it at all, then wait and see is the best approach, and don't water - at all - don't be tempted! I grow lots of cacti - they go entirely unwatered from autumn to spring. If anything is still green by mid-summer, then maybe water it.

To me, the top part looks like it's dried up, rather than being a soft rot. Cause unknown, but I end up with some like that when I try to grow species which can't cope with the winter temperature in my greenhouse (down to around 5C). Cold damage before you found it? The definite boundary between brown and green looks to me like the plant has sealed off the damage - sometimes you can break off (gloves or something needed!) the brown bit and it comes away at the dividing line - but I wouldn't try that now - likely just to damage it more.

I don't know about the brown at bottom right. Whether it's rot or just a harmless 'brown mark' like many plants get at ground level.

If this is to grow at all, then it's clearly not going to be at the top - it would have to be a new shoot from the side of the green bit.

And - before you rush to get smaller pot - plants don't die of 'pot too large'. It's only a problem if then overwatered, and all the soil which has yet to have any roots in it remains wet for ages.

weezyking666eDluiwl0

clarke.brunt said:

I don't think that anything you could 'do to it' at this stage is going to help. If you want to keep it at all, then wait and see is the best approach, and don't water - at all - don't be tempted! I grow lots of cacti - they go entirely unwatered from autumn to spring. If anything is still green by mid-summer, then maybe water it.

To me, the top part looks like it's dried up, rather than being a soft rot. Cause unknown, but I end up with some like that when I try to grow species which can't cope with the winter temperature in my greenhouse (down to around 5C). Cold damage before you found it? The definite boundary between brown and green looks to me like the plant has sealed off the damage - sometimes you can break off (gloves or something needed!) the brown bit and it comes away at the dividing line - but I wouldn't try that now - likely just to damage it more.

I don't know about the brown at bottom right. Whether it's rot or just a harmless 'brown mark' like many plants get at ground level.

If this is to grow at all, then it's clearly not going to be at the top - it would have to be a new shoot from the side of the green bit.

And - before you rush to get smaller pot - plants don't die of 'pot too large'. It's only a problem if then overwatered, and all the soil which has yet to have any roots in it remains wet for ages.

Thank you so much for this explanation. And yes, when I found it it was a cold and rainy day, I don't know how much time that cactus was outside, so maybe it got so much cold (it was sarting to get really cold outside, that's why I thought to give it a second chance, didn't want to leave it out there). 

The base of it it's only brown, not rotting, but the top of it it is and it's turning dry

KT53

As the likelihood is that the plant will die if nothing is done to it, you may want to consider cutting the brown section at the top off.  Use a sharp knife and make sure you cut into good material.  The top may callous over and put out side shoots.  Nothing to be lost by trying.

weezyking666eDluiwl0

KT53 said:

As the likelihood is that the plant will die if nothing is done to it, you may want to consider cutting the brown section at the top off.  Use a sharp knife and make sure you cut into good material.  The top may callous over and put out side shoots.  Nothing to be lost by trying.

At this point it's worth trying. Thanks for the reply