Humidity and bedding for my python?

My ball python is in a 20 gallon long tank. He has everything she needs in his tank to make him happy. Now, I want to know if it is Ok to mist down the tank even if I have aspen bedding. I wasn't really sure if I could do that. Is that fine even if I have aspen bedding for the substrate? And what other bedding could I possibly use for him if I didn't want the aspen bedding? I don't want bark if that is on your mind. I want something other than using aspen bedding, even though it works great. I just don't know what other I can get. Give me any ideas?