Helen wrote in message
The black plastic approach does work; but rarely quite as well as one
hopes. I'd use the heaviest I could get (old carpet is great),

Be careful with carpet, esp if you want to be organic. The carpet with the
foam backing usually contains lots of nasty, toxic materials that could /
will leach into your soil. Hessian-backed carpet is better.

Not only that, if you don't know where it's come from you don't know what
chemicals are on/in it. Has it been sprayed for fleas? What's it been
cleaned with? There is no way old carpet can be the organic way to start an
allotment unless it's 100% wool with a hessian backing and you know it's
clean of chemicals. Even new carpets are treated with anti-stain now.


Cardboard would be good, as would thick sheets of newspaper, esp if you
place the newspaper under the cardboard. Saying this, there are, AFAIK,
nasty chemical in the ink and non-white paper (eg FT)which will get into
the
soil, albeit in small quantities.

The cardboard / paper mulches will degrade by themselves, avoiding future
work by you.

And take your nitrogen with it.

The mulches you mention will only stop annual weeds from growing and unless
you intend to keep it there for a year or two the perennial weeds will still
be there when you start cultivating.
In other words it's a bit pointless in my opinion.

Strim the weeds off, await regrowth, then spray with Roundup. Wait until
everything is dead (and respray any that isn't). When everything is brown
and dead then dig it all in.
Your allotment will then be clear of weeds, perennial ones too, and you can
start cultivation immediately.
One or two sprays with Roundup will not leave any residual chemicals in the
soil after a few weeks as it breaks down. Certainly, according to everything
I've read, there will be nothing left by the spring when you start planting.

I too started our allotments whilst still at work so I know the time
constraints, don't make life even more difficult for yourself doing
something pointless.

--
Bob

www.pooleygreengrowers.org.uk/ about an Allotment site in
Runnymede fighting for it's existence.