Just thought I'd share this wth you. Each year I place upturned wire hanging baskets (chains removed) under my precious Hosta plant tubs & I don't get a single snail on them. (They obviously don't like assault courses!). My friend who doesn't do this, is plagued every year! The baskets are green so they don't look too abtrusive on the patio.
Whoops 'obtrusive' even! Also, the wire baskets I'm referring to, are the flat bottom kind. If you don't have these, you can always cut the bottom out of the mound shaped ones with side cutters & sit the pots into them (again upturned of course!).