Hi Judy is your cactus indoors or outdoors and what planting zone are you in? Could I also ask what kimd of cactus do you have?
Hello again Judy,
If you are lucky enough to own a large cactus, I would strongly urge you to visit a Library or buy a book on the subject, as it would be a shame to kill it with kindness!
Minimal attention is needed. Water sparingly with good draining soil.
A friend of mine gave me a small branch from her cactus. I planted it in a large pot using cactus soil. I give it a small amount of water every two weeks. She gave it to me four yrs ago and it is now about four feet tall. Very easy to care for.
What zone are you in? They thrive on neglect, and don't over water. And quantify "large" - are you talking indoor? Outdoor? In ground? In a pot? More details please!