There’s a thief in your garden. Seedlings are disappearing—and leaves and flowers are missing.
Suspect slugs. You can confirm your hunch that slugs are eating your garden by going outdoors after dark with a flashlight. Peek around the undersides of things, including bases of plants.
Slugs are very destructive. They can devour seedlings and damage young shoots and ripening fruit, but no plant parts are off-limits, not even stems or bulbs. If slugs are bugging you, here’s how to get rid of them—with the pros and cons of each approach…
Catch ’em while you sleep. You can just pour some beer into a deep pie plate and nestle it in your garden soil so that the pests can climb in…and drown. If leaving stale beer around doesn’t appeal to you, try a mixture of a few tablespoons of baker’s yeast or molasses in a few cups of water.
Alternatively, scatter something that slugs will crawl or slither under. Invert large leaves (such as cabbage), cantaloupe or grapefruit rinds and the slugs will crawl under them as daylight arrives—they don’t like daylight or hot sun. A few boards can work, too. You’ll then come out in the morning and round them up.
The downside to trapping: You’ll have to pluck slugs from the traps and, if they haven’t drowned, kill them or do something with them. Touching slugs won’t hurt you, but if you’re squeamish, use gloves. Drop the slugs in a bucket of soapy or salty water to kill them, then bury them in an out-of-the-way corner of your yard or put them in a bag and into the garbage. (If it makes you feel better, they’re 100% biodegradable!)
What else you could do with them: Turn them into bait! A neighbor of mine puts slugs on a rock island in the middle of her birdbath. If they try to escape, they drown. If they stay put, birds come by and dine on them. Note also that ducks and chickens eat slugs.
Not everyone is keen to kill slugs. You can try to block them instead. Due to their soft bodies, slugs cannot cross a barrier of diatomaceous earth, a coarse, powdery substance composed of fossilized silica shells of long-dead sea creatures—it’s too rough for them. Be sure to get “natural grade,” not “pool grade” (which contains chemicals that may be harmful to you and your garden). Sprinkle this generously around individual plants that you want to protect. Be sure to replenish after a rainfall.
Alternatively, wide copper strips will deter slugs, as their slimy bodies get a small shock when they try to slither across. You can use copper flashing from a hardware store. This material can even be wrapped around a potted plant if slugs are getting in there.
The downside to barriers: Rainy days diminish their effectiveness—and slugs travel happily in wet conditions. Because barriers often don’t kill slugs, the pests will make a U-turn and go find something else to nibble on. In other words, they’re still in the area.
Some gardeners prefer the convenience and effectiveness of commercially made slug baits, aka poison. Metaldehyde-containing pellets sold for this purpose work, but they also are poisonous to mammals (pets and people). If you want to go the bait route, I’d recommend products called Escar-Go! and Sluggo, which contain iron phosphate. These pellets interfere with the digestive tract so the slugs stop eating and die, but they’re much less toxic (though you still don’t want children or pets eating them). Always follow label instructions about placement, amount of product to use and timing—they’ll work best when you do. Baits need to be replenished every few weeks, depending on the product and conditions in your yard.
Any of the above approaches can greatly reduce slugs in your garden. But it also makes sense to ask yourself, Why is my garden attracting these pests?
You may have to surrender and give up growing lettuce or campanulas. Or your yard may be too shady and too damp—conditions you might be able to mitigate. Here’s how: Mulch less or not at all in areas where you’re having slug problems, pull weeds and thin out dense plantings. These actions will improve air circulation and reduce humidity in those areas.
You’ll make your backyard and garden less appealing to these slimy little creatures, so they won’t want to hang around.