Question
I have a small cactus and recently noticed that the top has turned a black brown color and started to rot away. Now I think it might be because I fogot to move it from the window overnight and it got cold (we live in Germany) Now I know I need to cut the rotten part off but is there a certain way that it need to be done?
I know that some say you have to clean the knife with a solution of some sort every time you cut the rotton part off, this will keep it from spreading.
What should I do once the rotton part is cut clean of it so that it doesnt rot more.
Please help


Answer
Erin,

First I must apologize for the delay in my answer. I have been out of town and not able to access my email.  

Some people will dust off the cut part with a sulfur powder or an anti fungal powder, both of which should be available at a nursery. If you make the cut at an angle so that water will not collect, you might not have to take any special precautions. It also might be a good idea not to water the plant until the cut heals (about a week or two).

Hope this helps, sincerely,

Greg