Slug and Snail Deterrents

Q. How can I keep snails off my basil? I've tried putting the plants on tables and surrounding them with snail bait, but no luck.

A. It's generally not a good idea to place bait near target plants. You're inviting snails and slugs to the area and hoping they don't move past the bait and go for your basil. Instead, you might try putting the plant containers on a tray and spreading diatomaceous earth in the tray. The critters don't like crawling in the stuff, because their soft underbellies get cut by the sharp edges of the material. Be sure, though, to use the type that's labelled for use on slugs and insects.

Says Jeff Gillman, associate horticulture professor of entomology at the University of Minnesota who researched garden remedies and myths for his The Truth About Garden Remedies (Timber Press, 2006), "The diatomaceous earth sold for use in swimmng pool filters is generally not effective on garden pests."

Another control method is copper. When slugs and snails come into contact with copper, their slime creates an electrical charge, so they won't cross over. Bend some copper around the rim of each pot, making sure that the snails can't access the leaves from some other avenue.

As for the bait, place it near plants you aren't trying to protect.