According to T-Rex brand substrates, Aspen is okay for ball pythons but Cypress or Desert Snow is BEST because of the humidity requirement. Aspen is best for cornsnakes, kingsnakes etc who are not humidity sensitive. I'm in FL so I used aspen last October because room humidity was 75% then I switched to Cypress in November when room humidity went down to 30%. So, either Aspen or Cypress is good depending on your humidity requirement. Misting Aspen is futile - it doesn't hold moisture.