Sam the Gardner, Well you ask a good question which has many variables like what type of cactus, some are very forgiving while others won't even give you a 2nd chance. One thing is common about them and that is that they like fast draining soil. Now as I mentioned others can be forgiving but most of the time ( not always ) It takes a mature plant to survive which begs the question, how did it reach maturity in the first place in that soil. Lol..

So, either the name of the cacti or picture of the cacti would help.

Greg