I have owned copper rings for years and use them to protect tender plants from slug attack. Apparently the slugs loath touching copper because the metal reacts with their slime and creates a mild electric current. It gives them an electric shock which repels them. This method works as well in the wet as it the dry, is 100% effective, and doesn't kill the slug.
Currently my set of rings is protecting young Brusels sprout seedlings but I needed to plant out climbing French beans, Early Trebona. Fortunately I had come across a copper sheet years ago that someone had thrown out and had saved it in my shed to make home made copper rings.
It couldn't be easier.
Take a copper sheet and some tin snips.
Cut the copper into strips. Wear protective gloves as the edges are sharp.
Clean with salt dissolved in vinegar. White vinegar is best but I only had malt. The salt is abrasive and removes the tarnish. This will increase the conductivity of the metal.
Use an empty bottle as a form to bend the copper around to form the ring.
Snip each end to form a means of connecting the metal.
Bend into a ring and gently test your connection holds. Then very gently place around your plants. Be careful not to damage the stems while you are connecting the copper ends!
Slugs will not climb the copper to eat the plants. Just be careful no part of the plant can be reached outside the copper or it will be vulnerable.
Maddy Harland is the editor of Permaculture - practical solutions for self-reliance, a magazine filled with useful and inpiring features, stories and ideas about all aspects of sustainable living from gardening and farming to green building and renewable technology. Check out a free digital copy HERE. You can subscribe to the print edition HERE.