Please see Part 1 of this article for more on the natural history and care of Rough and Smooth Green Snakes (Opheodrys aestivus and O. vernalis).
An ambient temperature of 70-76 F is ideal. A basking site of 80-85F should be available as well.
There is some evidence that, in contrast to most snakes, Green Snakes benefit from exposure to UVB light. A moderate-output bulb, such as the Zoo Med 2.0 should be provided.
As with most diurnal animals, Green Snakes will also benefit from the provision of a UVA-emitting bulb (incandescent UVA bulbs will also provide heat for the basking site).
Green Snakes are more difficult to provide for than typical rodent-eating species, but well worth the effort. Those who do well with these snakes have one thing in common – they consistently provide a highly-varied diet. Green Snakes will not thrive for long on crickets alone…during times when they are a mainstay, crickets themselves be well-fed before being offered to the snakes.
Wild-caught grasshoppers, smooth (non-hairy) caterpillars, moths, crickets, tree crickets, katydids, beetle grubs and harvestman (“daddy longlegs”) should comprise the bulk of Green Snake diets whenever possible. They take a great many spiders as well, but I hesitate to recommend collecting these to folks unfamiliar with potentially dangerous species.
Other commercially available insects that can be tried include roach nymphs, waxworms, newly-molted (white) mealworms and super mealworms, butter worms and silkworms. Canned silkworms may also offered via feeding tongs, but many Green Snakes are reluctant to feed in this manner.
Green Snakes have high metabolisms and should be fed 3-4 times weekly; in contrast to most snakes, they decline rapidly in condition if not fed often.
Drinking water is essential – more so than for most snakes. A water bowl should always be present, but some individuals will drink only from drops sprayed onto leaves and branches.
Green Snake fans usually favor Garter Snakes as well; please see Meet the Garter Snakes for more info.
Further natural history information may be found in this article.
Learn more about collecting insects here: Collecting Insects
Smooth Green Snake image referenced from wikipedia and originally posted by atrahamrepol and Ravedave