Copper tape repels slugs and creates a finished, tailored look. The tape "comes in different widths to accommodate the size wood you choose to build the raised beds," says Luna. If you use 6-inch-wide copper tale, it will give you a 2-inch lip on each side of a 2-inch top edge. A 13-foot-long roll of Copper Slug Tape (1.25 inches wide) is $9.95 from Gardeners Supply.
Penny Ball for the garden. Pennies in the garden repel slugs and make hydrangeas blue. I love this idea. It looks old and new and beautiful. I need this to keep the slugs off my strawberries! - Gardening For You More
These copper bands are one of the best, non-harmful slug repellants around. Slugs and snails hate copper because it causes a harmless electric shock-like reaction when they come into contact with it, so they crawl away. Bend them into rings and push them into the soil at the base of your plant.