Not Tape Or Mesh: There's A Better Copper Hack To Keep Slugs Out Of The Garden

We may receive a commission on purchases made from links.

The best gardeners always look for ways to improve a raised plant bed, so when pesky slugs try to sneak in for a snack, they turn to clever hacks to keep them away. Some try copper tape or mesh, which allegedly repel slugs because their moist bodies experience a shock when exposed to copper. Another theory suggests that copper is somehow toxic to the slugs. However, these aren't scientifically supported, and evidence indicates that motivated slugs can tolerate copper enough to get past the barrier.  So, when these and other popular garden myths to deter slugs don't work, it's worth a shot to DIY an "electric fence" instead. As an added bonus, the tiny zap the slugs receive won't hurt them, but is enough to make them do a quick about face!

Slugs shouldn't be exterminated outright because they are valuable contributors to the ecosystem, in part because they are the food of choice for creatures that we rely on to keep nature in balance. They are also important because they nosh on plant waste, making your DIY compost even better for your garden.

To make this slug-repelling fence, start by gathering some materials. You'll need uncoated copper wire, a 9-volt battery, 9-Volt Battery Clip Connectors, a small drill, and a plastic container large enough to fit your 9-volt battery, with a removable lid that provides a tight seal. If you have a wooden garden bed, you'll also need a staple gun and staples. If it's metal, electrical tape or wire-threading clips and double-sided tape should do.

Once you have the materials gathered, it's time to DIY your copper electric slug fence. First, attach the copper wire around the bed. The process will be slightly different depending on if it's a wooden or metal raised garden bed. If it's wooden, you can staple the wires to the walls of the bed without problem. If it's a metal bed, you'll have to insulate the wire. Suspending it with a product like these Command Clear Mini Light Clips could work to keep the copper wire from touching the surface. For a wooden bed, keep tension so the wire doesn't droop between staples. Use a staple gun to attach the wire all the way around near the top of the bed. Once the two ends meet, connect the ends by twisting them together, then trim. 

Next, move about 3/4 inch lower, and repeat the process with another wire, wrapping it around the bed just below the first wire. Don't let the staples or wire from either layer touch each other or the battery will short. They should be on two separate loops around the bed.

Drill two small holes in your weatherproof plastic container. Below the two copper wire strands, attach this container to the wall of the raised bed with screws. Then, thread the ends of the battery connector through the small holes in the plastic container. Using electrical tape, connect the negative end to one copper loop, and the positive end to the other. Lastly, connect the battery to power up and close the container lid. If you have a multimeter, check the voltage to make sure everything is working correctly.

There are a few factors to consider when installing this slug-repelling electric fence. This hack does require a decent amount of know-how with tools like batteries, wires, and drills. However, users report that it is very effective at deterring pesky slugs, and it's pretty inexpensive to put together, so it might be worth a shot if other methods have failed. 

Second, because one wire is negatively charged and the other is positive, a slug will have to touch both wires at the same time to connect the circuits and feel a small shock. This design also means than any slugs already existing within your garden bed won't be able to get out, so remember to hand-pluck any occasional stragglers. It might take some time, but you'll know it's working if the slug population in your raised bed is far fewer than before.

The system also needs to be checked frequently to make sure the battery still has charge and the wiring is still properly in place. If you don't have a multimeter at your disposal, you can check the battery's charge by disconnecting it and touching both terminals with the tip of your tongue. A little tingle means there's still a charge. Speaking of the battery, don't fret about the safety of working with a 9-volt. Although it produces a current, it is not strong enough to harm a human. If all it's going to do to a slug is make it turn back around, a person should be just fine!