By Joel Winters
Issue #142 • July/August, 2013
I live in a small clearing in a big forest. This is on the rainy side of the mountains in the Cascade foothills. Slugs are underfoot nearly year-round and have been a big problem for me in the garden. After last year’s long spring and wet summer I knew I had to do something if I was ever going to enjoy what I planted. I conceived the idea of an electric fence for slugs. It’s just now completed and for the past week my beds have been slug-free.
Here’s how it works. Two varnished copper wires are laid down in parallel around the lip of a raised bed. The insulation is scraped off the top surface of the wires and each wire is connected to a surplus 12-volt battery. The wires are about 1/2-inch apart. Any slug has to cross the lip of the bed, treading over both wires. Upon touching the second wire, the slug completes the circuit. Most slugs test the second wire a few times then turn back unharmed. A few unfortunates have been trapped between the wires and just sort of melted. Like any animal, slugs quickly learn to respect a hot wire, thus casualties become a rare thing after a few nights.
Get a few ounces of short copper tacks, a roll of sturdy, but not too thick varnished copper wire, some insulated automotive wire, two alligator clips, and any 12-volt battery.
Nail the tacks partway in, staggered slightly at one-foot intervals. Roll out your wire and loop them once around each tack. Try to keep the wire straight and tight. With your wires up, drive the tacks home. Wipe a knife edge across the top of the wires to scrape clean of varnish. Clean a spot on both wires completely free of insulation and solder jumper wires to your hot wires. Hook alligator clips to the end of your jumpers and hook up to a battery set beside the bed or do a whole garden by hooking jumper wires to multiple beds.