CanPlaceOn commands not working properly

I've been having trouble with NBT tags lately, but this particular problem is pretty annoying. I'm trying to make an adventure map, but the CanPlaceOn NBT tags don't seem to work. The command that I'm using is: /give thedarkcave minecraft:stone_pressure_plate{CanPlaceOn:snow} and no, before you ask, I can't put 1 0 on the end of stone_pressure_plate because then I get a syntax error.