Latest Gardening Fashion: Slug Collars!

Split Copper Collar on seedling

Nope, I am NOT putting collars on the slugs, nor am I wearing a collar fashioned out of slugs! I'm making collars to deter slugs in the garden. Slugs are a gardener's problem almost everywhere, and living on the creek, my problems are exacerbated by also having snails who do the same kind of damage.

Years ago I read that slugs will not cross a copper strip because it gives them a jolt, so I bought a roll of 1 inch copper tape to put down on the top edges of my raised beds. It didn't work! 

Recently I read that copper actually IS effective (it was a science experiment), BUT to work, the slugs have to crawl across 3 inches of copper to build up the galvanic action between their slime trail and the copper. THEN it works!

Two weeks ago I ordered a 2 foot piece of 12 inch wide copper from Basic Copper. It wasn't cheap... but it is thick enough (16 mil) to re-use for several gardening seasons... and when it gets too beat-up and out-of-shape to use, I can sell it as scrap copper.  I probably could have used a thinner gauge of copper, but I really want to be able to use them over and over.

 

The first collars (made today) were for larger plants already in the ground, so the copper needed to be split to go around the stem. (I'm going to make all of them that way... it's easier.) I thought about taping the collar split ends together, but that would just give the slugs a place to climb that wasn't copper. In putting them around a plant, I found I could just squeeze the copper "tube" around the stem and the ends would overlap... then I pushed the collar into the ground just enough to hold it in place. 

What I did:
I cut a 4 inch wide strip off the copper sheet, then the first strip into 6" lengths... that gives me collars 4" tall, enough to push the bottom into the soil and still have 3" or more for the slugs to climb. I'm testing it tonight before I cut any more, but I have every confidence the science experiment was correct. I put those first 3 collars on small tender seedlings this afternoon, and will check them in the morning. The only thing I might change is either taller collars so more length can go in the soil for stability, or wider sections to roll into split tubes.

Update:
It Works! I will, however, make them a bit taller and wider just for my own convenience.