While snails can be perplexing garden pests, there’s no reason to fight back with toxic chemicals.
Copper is a very effective and safe snail repellant.
The snail’s slime secretions react with the copper to provide a mild electric sensation that snails instinctively avoid. Simply add bands of copper wiring or copper tape at the base of any plants that are regularly devoured by snails.
Also, make sure that no snails are trapped on the plant when you place the copper, or that no bridges exist between plants. With a little time and patience, you’ll start noticing that plant damage from snails is greatly reduced, and often eliminated.