How to Get Rid of Slugs with Copper

Robert Pavlis

Slugs in the garden can be a huge problem and apparently copper is a good slug repellent. If you encircle your plants with copper tape, it will keep the slugs out. It must work – since there are a number of copper tape products on the market designed to get rid of slugs. But does this really work?

How to get rid of slugs with copper
How to get rid of slugs with copper

Why Does Copper Work?

There are two reasons given for copper working as a slug repellent; toxicity and electric shock.

Copper is a known poison for many organisms and some copper chemicals are used to disinfect and kill organisms. It seems to make sense that copper tape or copper wire would have the same effect. If you think about this for a minute you will realize this can’t work. Most homes in North America use copper pipe to deliver water in our homes. If it were toxic – would we be using them?

Copper compounds may be toxic, but copper metal is not.

The green patina developed on copper metal over time is a copper carbonate salt and could be toxic.

The second claim is that the slime from slugs connects with the metallic copper and the slug gets a small electrical shock from it. This is unpleasant and slugs stay off the copper.

I have not been able to find any scientific reference showing that this is true. It is just repeated thousands of times. So let’s apply some logic. You can create a simple battery by inserting copper wire and a galvanized nail into a lemon. This will produce a small current that is measurable. You need 3 important components to make this work; two electrodes of different metals, and an electrolyte–the juice in the lemon. If you want to see a lemon battery in action have a look at this video.

Compost Science for Gardeners by Robert Pavlis

In the case of the snail we have the copper, and the electrolyte in the form of slug slime.The second electrode is missing. Also missing is the connection between the two electrodes which allows the current to flow. I don’t believe that putting slime onto copper will produce an electric charge.

Does Copper Repel Slugs?

Let’s look at some video evidence.

YouTube video

Source: Does Copper Work on Slugs? See and Decide for Yourself! Just for fun!

 Copper pennies and wire do not seem to work. Most products on the market are a type of copper foil or copper tape so this might work better and in fact some people suggest that a wider strip is better than a narrow strip.

YouTube video

Source: Copper Tape vs Slugs

That seemed to work quite well. But what about this video?

YouTube video

Source: Garden Pest Update: Slug vs Copper

Maybe some slugs hate copper more than others.

And this one:

YouTube video

Source: Slugs vs Copper Tape

How to Get Rid of Slugs

Jeff Gillman, one of the Garden Professors, commented “When I’ve tested copper the slugs seemed to have a slight preference for not crossing it, but would if that was what they need to do to get where they were going. I’d call it a mild repellant” . I think this is a good summary. Slugs will not go out of their way to cross copper in tape form, but it is not a fool proof solution.

This myth is busted!

Other popular methods for getting rid of slugs include coffee grounds, and beer. For more information on these methods have a look at:

Getting Rid of Slugs With Coffee Grounds

Do Beer Traps Kill slugs

References:

1) Photo Source: Aspen Grove Gardens

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Robert Pavlis

I have been gardening my whole life and have a science background. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

75 thoughts on “How to Get Rid of Slugs with Copper”

  1. I’ve seen so much on using a ammonia to control slugs but nobody says it’s OK or NG to use it on vegatables (health wise). If you have any thought on that I’d appreciate hearing them. Seems the gas should simple evaporate but I wonder if somethig bad happens before it goes.

    Do you know anyone who uses it on vegetanbles?

    Slugs on vegetable is an extrealy important topic so I wonder why nobody treats it.

    Reply
  2. In the past I have had some pretty good success with a solution of ammonia sprayed on the slugs at night. You can get ammonia at the hardware store and dilute it. Use trial and error to figure out the concentration. Ammonia is also used as a fertilizer so doesn’t seem to hurt the plants too much (although can burn them a bit). It’s probably a horrible death for the slugs (they start foaming) but if you have a bad infestation you may have to use desperate measures. Obviously no good in an organic garden. I use Sluggo these days, which is.

    Reply
  3. I have read a few of the articles here. I found you when I was looking up as to why molasses is good for compost. It makes complete sense that when the molasses was all consumed that there would be a starvation problem. Humans energy often crashes when the sugar we consume is burnt up.
    Any way, to the slugs. I used to do a bit of gardening a few years ago and I tried beer, egg shells, coffee, those green pellets with copper in them and nothing worked. The best way is to control them by picking them up and buffets of greens here and there. The knife video with the slug crawling over it was quite fascinating. I watched the snail and slug move along the sharp part. Any one who knows anything about knives is that to cut you need to slice. Many swords were designed with that in mind.
    And as for using beer, they loved it, but there were times during very hot days that the rotting corpses of the slugs in the beer stank. While beers kills them it also attracts them from all over.

    Reply

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