By Larry Hodgson
First, for the thirteen gardeners on the planet who have not heard that you can attract slugs with beer, a bit of an explanation.
A slug beer trap is a snap to prepare. You just insert a small dish or bowl into the ground and pour some beer in. Any beer will do, even non-alcoholic beer. Slugs, attracted by the smell of malt, are supposed to fall into the dish and drown. Moreover, if you try it, you will indeed find a few drowned slugs marinating in the beer the next morning. So, in principle, it seems to work.
But the time-lapse video above reveals what really happens. Most slugs that visit the trap are content to drink some beer and then continue on their way without any negative consequence. Some even slide right on down into the trap, wallow in the beer then climb back out, apparently very satisfied with their night of drinking. Others (a small minority) also descend into the trap, but don’t leave: they drown and they’re the ones you find belly up the next day. (Nobody knows why some slugs drown while the majority remain uninjured: that remains a mystery.)
Another problem: the odor of malt attracts slugs from afar and therefore actually increases the population of slugs nearby. Therefore, damage to leaves actually increases. It’s like a sip or two of beer gives the slug hordes the munchies. Therefore, plants near the trap actually suffer more damage than plants located far from the trap. In other words, the slug beer trap, when used as usually recommended, does not protect your plants and can even result in even worse damage.
However, there is a method that ensures a beer trap really does reduce the damage caused by slugs. Don’t put the slug beer traps out in your own garden, but instead recommend the method to your neighbor. He’ll try it, be satisfied with the few slugs that drown in the traps, and attract all the slugs in the neighborhood to his garden rather than yours.
OK, that was a bit underhanded. So, let’s be more magnanimous. Place the trap in your own garden, but as far as possible from the plants subject to slug damage, such as vegetables and hostas. This will draw slugs into areas where their leaf eating is not a problem. Clean and top up the trap every few days and you should see your slug population decrease, especially over time.
Text based on an article originally published in this blog on July 15, 2015.