There are baits, brews, traps and tubs you can get rid of slugs with (okay I couldn’t think of anything else that started with the letter t…), but why not just use what you may already have in and around the house? How about the cold cuppa that goes down the drain? Put it to use, along with the grounds.
The Hack: brew up a second cup for the slime balls in your garden. Let it cool, or keep the half-a-cup that you didn’t finish, and pour it where they’re having their breakfast. Cold coffee doesn’t hurt the plants, and it may perk them up, too!
“… This sounds like scientists chatting around the water cooler, so let’s look at a more real-life example: A cup of drip brewed coffee has about 115 milligrams of caffeine, an espresso (and percolated coffee) about 80mg, while instant coffee has about 65mgof caffeine. Thus, drip brewed coffee is about twice as strong as the instant stuff, which means you want to use drip brewed coffee for repelling slugs and snails.
Coffee grounds are already recommended as a home remedy for keeping slugs and snails at bay. Grounds repel slugs, Hollingsworth found, but a caffeine solution is much more effective, he says: “Slugs turn back immediately after contacting the [caffeinated soil].”
Personally, I’ve had good results (if you want to call making a slug uncomfortable “good results”) with sprinkling coffee grounds around plants as well as spraying slugs with brewed coffee–you know, the stuff that doesn’t get consumed in the morning and tastes really bad when you try to microwave it in the afternoon? Many other gardeners have told me they’ve had similar luck. …”