Whilst this may sound like the flippin' obvious... I thought I'd share it anyway. I used a pile of carpeting to suppress weeds on some planned path areas about 3 years ago. I have finally got round to attending to this area and, no surprise, weeds have grown through/in the fabric. It was a real mess and a pain to remove everything, but the soil underneath it now has the most perfect structure; in fact, much too good for a path. So I would say carpet is great as a temporary measure but don't use it as a permanent material on your allotment.
Couldn't agree more....when I took on my plots last winter, it was a nightmare digging out miles of heavy wet soggy carpet, much of it had masses perennial weed roots growing along underneath it.
Worms love it under carpets, which helps with the soil prep.
But they are horrible to remove, especially if they have been there a few years, and any backing can break down and leak toxins into the soil.
It's for these reasons they are banned on a lot of sites.
The only pros are that it is heavy and easy to get hold of and it smothers weeds very effectively. I suppose that the worms do like it under them - but then again on my plot slugs also like sitting under the edges and mice/voles love them as ground cover to dig their network of tunnels under.
So the cons are that the mice come out and help themselves to my crops as do the slugs. Weeds will find any tiny weakness in the middle of the carpets and push through and around the edges the weeds will quickly start to come over the top. They do break down and leave undesirable stuff in the ground too.
I am delighted that I have finally conquered the final area on my plot using the carpets. All of the carpet I have used were there when I took it on - some of it under an inch or two of composted weeds with roots pinning it firmly down ... removing it is such a nightmare when it's that deeply embedded.
So it works as a technique of clearing ground - but it's definitely not a permanent solution and if you don't keep checking to see if the weeds round the edges aren't invading - it can be far more trouble than it's worth.
They are banned from our site due to contamination. When I took on my plot there was so much of the stuff all over the plot in random places as well as the paths. It took ages to clear it, and of course left me with a lot of rubbish to get rid off. I still find bits of carpet when digging and wouldn't use it personally.
I've got random carpet in my plot, more often than not with another layer about 6 inches below. It's horrible to remove. Wish it was banned on my site.
We have a total ban on carpets on our site. Some of them moan and groan but once they are told why the carpets come off very quickly. We use a lot of weed membrane much better stuff.