Well, I recently read somewhere that using copper strips an inch below and inch above the soil will generate just enough electricity to keep slugs and snails away from your plant, make sure you inspect daily since snails will use branches, leaves, sticks and etc. to cross the copper strips
I believe this information came from Mogie and if you type slugs or snails in the search box, then look for the thread entitled "wtf will slugs do to my seedling"
Peace
K-town