"Gordon Filby" wrote in message
...
Hallo,

My non-gardening son has just told me of a report he'd read/heard that
surrounding plants with a copper wire keeps away snails. Apparently, it
reacts with their trail fluid (sorry don't know the English) producing
something they don't like.


I've watched snails trying to cross copper strip. They definitely
did not want to remain in contact with it for any longer than possible.
However, they could cross it if they wanted to. This was on a
flat horizontal surface. I'm relatively sure that if its on a vertical
surface its harder, and that overhangs of copper are almost impossible for them
to get past. I have snailproof seed beds consisting of a large plastic tray,
which will hold six seedtrays sideways, supported off hard standing on
four aluminium tube feet 10cm high. At the tops of the tubes where
they meet the tray are cones of copper wire mesh sticking out about 10cm.
So far, its snail and slugproof. After a month or so outdoors the
metal dulled down and its no longer obtrusive. And yes, you can cut copper
sheet, foil or mesh with tinsnips. Scissors also work for thinner grades
and those all-purpose shears things are also quite good.

As for how it works, I have no idea. The electrical theory seems
unlikely to me. The copper *and another metal* together with the slime
would produce a battery producing a volt or so - and maybe they're
sensitive to that. But in general, where is the other metal? I'm
much more inclined to believe that they find copper salts extremely
toxic and avoid them. It could be tested with platinum or gold strips
attached to small batteries. Unfortunately I don't have the required
certification for animal experiments.

j