Suggested proportions of water to vermiculite range from 1:1 to 1:4 (by weight). Keeping the eggs too moist has been reported to cause egg death. Some institutions allow the medium to dry out significantly during the last four to six weeks of incubation.

Temperatures should range from 79 to 82 degrees Fahrenheit with incubation lasting from 124-140 days. Eggs laid in May to July hatch in October to December. However, in the wild, eggs laid in the summer over-winter and hatch the following spring. (Goldberg and Lowe, 1997)