Slug fences

By Michael Bomford

Slugs can be a major pest in areas that are heavily mulched. Organic growers often use organic mulches, such as newspaper and straw, to prevent weed growth, hold soil moisture, promote water infiltration, and add organic matter to the soil. When I worked as a gardener at the Gesundheit Institute in West Virginia I had the frustrating experience of transplanting lettuce into heavily mulched beds in the evening, only to find the plants completely destroyed by slugs the next morning.

I remembered that my mother used mesh fences to protect sensitive transplants from slugs in her garden, and I wanted to know if it worked.

I transplanted 36 new lettuce plants into spots where plants had been eaten the night before, and randomly assigned 18 to be fenced and 18 as unfenced controls. I cut 18 6 x 10" (15 x 25 cm) strips of wire screen door mesh.

I folded each strip around the open end of a tin can, to make a cylindrical fence with a 1" (2.5 cm) cuff at the bottom.	Where the wire mesh overlapped I folded wires that protuded from the bottom layer over the top layer to strengthen the cylinder.

I pressed the open end of the tin can about 2" (5 cm) into the soil, so that the fence encircled a transplant.	I removed the tin can, and re-used it as a form for the next fence. Each fence took less than 5 minutes to construct and install.


The results were clear: The next morning all 18 of the transplants inside fences were alive and healthy, and all 18 of the transplants without fences had been eaten.	Slug mucus was caught on the top of some fences, suggesting that slugs had climbed the walls, but hadn't been able to go over the spikey top.

Updated March 7, 2008