Q&A: How do I get rid of snails in my garden?
A: Snails, like slugs, are a bothersome pest - they can destroy young plants. You are doing the right thing and short of handpicking them, you can try Diatomaceous earth ï¿½" it's a white abrasive powder made from ground-up, fossilized shells of small sea creatures. It punctures holes in the skins or shells of many insects and caterpillars, including snails and slugs. However, it also kills bees, so use in the early morning, before flowers open. You may have to reapply after heavy rains. You could also eliminate hiding places such as dark shady hiding places like branches on the ground. Larger lids like from a jar, holding some beer may attract them may also eliminate them... just place right on the ground level and clean them up in the morning as they will only travel at night.
Hope this helps,
Astrid Strader, Horticulturist
Etobicoke Master Gardeners