Believe it or not, this comes from the University of Hawaii and was discovered by accident while trying to do something else entirely.
COFFEE KILLS SLUGS & SNAILS. Make very strong caffeinated coffee. Mix half and half with water and put into a trigger or compressed-air sprayer. Spray on plants and the ground that snails & slugs travel on. As they move over the treated areas, they take up the caffeine through their pseudopod (foot) and it gives them heart attacks in 72 hours.
Cheap coffee works as well as the more expensive sort. I use espresso because it's more finely ground (works better in my machine). I also run the water through the grounds more than once to extract as much as possible - I'm filling a 4 gallon backpack sprayer.
My snail problem is worse in my daylily field than anywhere else, but the Hostas look better this year for this solution, too. Cheers for an elegant and simple solution to nasty critters.
