Beer Traps & Barriers

Beer Traps

Almost everyone who gardens has heard of beer traps for slugs: fun for them, easy for us, non-toxic, and the chickens enjoy the alcohol-marinated mollusks.

To make a BEER-TRAP, cut half-circle entries in the rim of a margarine or yogurt container.  Bury the container an inch or so in the ground near any susceptible plants like veggie seedlings. Make sure to leave about an inch of container above the ground so helpful beetles don’t fall into the trap. Fill with an inch or so of stale or cheap beer.  Yeast mixed with water can be used as an alternative to beer. Finally, replace the lid to keep out rain. Slugs will crawl in and drown (happily we assume).

Homemade beer substitute

1 cup of water
1 teaspoon of sugar
1 teaspoon of flour
1/2 teaspoon of dry yeast

Check the traps in the morning. Empty into compost or feed to the chickens or ducks or empty into a jar of soapy water.

The down-side of beer traps is that they must be replenished every few days and may only attract slugs from a few square feet at a time. We use one or two in each 4’ x 8’ raised bed, and only in the spring when the slugs are rampant and the seedlings are especially vulnerable.


Barriers are best used around raised garden beds, individual plants, containers or rows of juicy seedlings. Barriers fall into two general categories:  bands of rough material that deters slugs from crawling across the barrier and copper or battery powered barriers that work like an electric fence.

Rough Stuff

Sharp, irritating or dehydrating barriers include crushed lava rock, pecan or filbert shells, wood ashes and course gravel. Like walking on a gravel road in your bare feet, the soft-bellied slug is reluctant to crawl over such raspy materials to reach your tasty plants.  Just place these materials in a band or circle several inches wide around any plants you would like to protect. Remember to keep the material away from the plant stem and concentrate on new seedlings and any of the slug or snails favorite plants like lettuce or marigolds.

Crushed Lava Rock Much less expensive if you but it from a landscape supply company by the yard. Most places will let you fill a bucket for just a few dollars.

Eggshells Not recommended – the egg residue can actually attract slugs!

Wood Ashes Also adds potassium to the soil and raises the pH like lime.

Diatomaceous Earth

If you live in a dry climate diatomaceous earth is one of our favorites.  It’s easy to obtain at feed and garden stores, fairly inexpensive and very effective. It feels powdery to the human touch, but is actually made of abrasive bits of tiny ancient fossilized sea critters. When a slug or snail trys to cross a DE barrier it becomes lacerated and begins to dessicate from those hundreds of tiny cuts.  DE is not as effective in wet climates, as it becomes soft after rain or watering and must be reapplied frequently. If you use drip irrigation DE can be an ideal solution.

Copper Barriers

Another common and easy-to-use barrier for slugs or snails is copper tape, strips or mesh. Copper reacts with slug slime, causing an unpleasant disruption in the nervous system, apparently feeling much like an electric shock. One of the best things about copper is the fact that it can be used over and over for years to come.

You can buy self-adhesive “Slug Barrier Tape” from garden sources or purchase rolls of 2” copper flashing from a home improvement store. The tape is best used around raised beds or containers. Flashing can be partially embedded on edge in the soil making a little fence around a bed or plant.

Slug Shield is a copper-based mesh that can be wrapped around the stem of larger plants.

There is also an electric “fence” for slugs on the market. The Slugs Away barrier is powered by a 9 volt battery and consists of a 5” x 24’ barrier that delivers a little shock to would-be intruders. It will not hurt humans or pets, unless your pet is a slug.

The Final Step

With any barrier it’s a good idea to sprinkle a handful of bait inside the barrier to kill any slugs that are hiding in the soil and a bit outside so slugs don’t just smell the bait inside.