Help!!! Recommended snail supplies?

Hi! I have recently discovered a garden snail within a box of leeks at my work. It was frozen but came back to life once i got him out and everything. I now have him sitting in a jar with a hole in the top and mist it with kale at the bottom for him to eat. Im trying to look at substrates or anything to put in the bottom of a tank im about to buy but want to make sure its not too acidic. I live in a town where we only carry a peat and sphagnum moss mix and am ordering everything off amazon unfortunately. Any help would be wonderful thank you!