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Wales, United Kingdom
You know those diagrams in science textbooks that show the water cycle? Water evaporates from the sea and cools as it rises over the land until it condenses into clouds. Well that's where I live - where the clouds are born. It's very beautiful here, and it's also very damp. I don't yet know what I'll be writing about here. I had a blog a few years ago called, "Growing Things and Making Things," and there will be some continuity with that, but my life has moved on since then. I'm at a stage of reflection and re-evaluation - you could call it a mid life crisis - and this blog will reflect that. There'll be posts about things I'm doing - foraging, cooking, crafts, daft experiments (which may overlap with any or all of the other three) - posts about my thoughts on life, photos of beautiful Welsh scenery, maybe some Welsh language, and probably a bit of politics. Because it's important.

Monday, 18 June 2012

Copper wire as slug deterrent: a test

Amongst many things that are supposed to deter slugs, a strand of copper wire allegedly gives them an electric shock when they try to cross it. I was chatting to Dad yesterday and he mentioned this, suggesting that two strands might be necessary to make a circuit. Slugs are currently munching their way through our strawberries and the pots are quite hard to defend by other methods, so I thought this would be worth a go.

I took a bundle of electrical wire from the old washing machine and stripped a length, which turned out to be stranded. That should be ideal.

I took the strands out to the patio and started stringing them round the strawberry pots when I thought that it might be an idea to test the theory first. It shouldn't be too difficult - I'd just need to find a slug.

It took me about ten seconds to find this big boy hiding in some leaves...

... but he was sleepy and couldn't be persuaded to go anywhere. It didn't take much longer to find this little guy...

... who was much more sprightly. I put him on the patio in a circle of copper wire (several strands) and waited.

The first encounter with the wire was encouraging. When his antenna touched it, he withdrew and turned away.

After a couple of attempts, though, he braced himself and slid straight across.

Test result: Copper wire completely ineffective as a slug deterrent, at least against this slug.


  1. Sorry, I had to laugh at this, I was considering putting copper wire around my raised beds, but I dont think I will bother now. Perhaps that was just a very brave slug, perhaps you ought to experiment with a few more!!!!

  2. Sleepy slug!! You almost make it sound rather loveable, not to mention the plucky little fella who breached your defences. I'm about to go into the garden properly now for the first time in days (the hurricane has abated somewhat). I dread to imagine what I will find. I fear slugs may be the least of my problems... everything has been ripped to shreds by the wind. Have you tried coffee grinds / egg shell? Apparently they can't stand straight-edged stuff. I think you need a LOT of coffee to make it effective though... I am going to collect mine and chuck 'em to the ducks I think...

    1. We don't drink coffee, but I've tried egg shells, ash and grit all together and the little buggers still crossed the lot to eat my pumpkins.

      I've heard of a slug killing a duck. Their defense mechanism is to form a hard ball (poke one - you can see them do it) and one did this halfway down the duck's throat, choking it. Presumably that's why it's a good defense. I don't know how big a risk this is, but thought I'd pass it on.

  3. Oh. That's interesting because people often ask me advice and copper wire, egg shells, grit etc are the things I usually tell them. I don't have a problem with them so I've never had to experiment. (I have plenty of other problems in the garden so don't think I get off lightly!)

    1. It's possible that we have particularly tough slugs here in Wales. They also eat onions...

  4. Thanks for this post - it is really useful to know copper doesn't work!

  5. Have you tried a bigger diameter cable as that would naturally give a bigger shock.

    The cable you used looks very small not even 0.7mm.. I am going to try 2.5mm from a old reel I have left over from when I rewired the sockets...

    Also I was reading the which magazine leaflet and aparently if you spray your pots with WD40 (oil in a spray can, in the UK) the slugs can not climb the pot..

    For beds and cropping copper tape/rings, heather and seaweed is supposed to help but not sure on them.

    1. This was very thin wire, it's true. I did wonder about thicker wire, or the copper tape you can buy from garden centres, but haven't tried it yet. Do let me know how you get on with the thicker cable.

      With WD40, I'd be worried about it washing off in the rain and ending up in the soil or a stream. My neighbour sells non-stick tape, which he says is very popular with gardeners. I must ask him for some so I can give that a go.

      I don't know about heather, but I suspect with seaweed it's the saltiness that slugs don't like. Most plants don't like that either.


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