I guess it would depend on your weather, how diligent you were in making sure temps were ok, etc. Can't stress enough to keep glass tanks out of direct sunlight. Then what will you do with it come winter time? Releasing a snake that's spent any time in captivity isn't a good idea. Besides, if you don't spend a lot of time out there, what's the point? Really, the fascination with garters, to me anyway, is in observing them. If they're not somewhere where you can see them you may as well have another corn in a box

oke: Sorry, I love my corn, but his empty looking tank really doesn't need to be in sight at all times
Right now, in one garter tank I have one curled up in his driftwood log staring at me and one climbing the driftwood log and up onto his vine. In the other garter tank I have two adults curled up together looking cozy on their basking rock. In my corn tank, I have one very healthy corn who had a perfect shed for me overnight and ate this morning... I know he's in there somewhere