I actually do let my ball out, but in one section of my yard only, away from where the dogs are allowed to go. I don't use any pesticides, or fertilizer, and the house next door to me is abandoned, so no chemicals on that grass in over 4 years. I never take her out if temp is below 80, or above 90. Generally around late afternoon/early evening during the summer, right about the time she wakes up anyway. She seems to enjoy it, an explores in periscope mode.

My corn snake on the other hand, I never let down onto the grass,he would be gone in a second!