Cactus Societies & Clubs
The best source of information is a cactus club or society in your area.
There is always someone there that has solved any problem you might come up with. They also usually have a library of books for you to use. If you don't know where the closest club is, contact:
For CSSA inquiries, contact the Business Manager,
Chuck Everson, Bookseller
1444 E. Taylor St.
Vista, CA 92084-3308