I want to cover quite a large area (about 20m x 7m) with a ground cover mat
to stop weeds growing by excluding sunlight, but letting rain penetrate to
water the trees which will stick through the ground cover. Any suggestions
for the best & most cost effective sort of membrane etc (not old carpets
please!).

Simplest is a weed supressing membrane and should be available from a
good garden centre, but perhaps cheaper on-line.
Mike

wrote:
Simplest is a weed supressing membrane and should be available from a
good garden centre, but perhaps cheaper on-line.

Preferrably one of the black ones. But you do need to know what weeds
you are trying to suppress. Bamboo and to some extent thistles will
laugh at your puny attempts to trap them under finite areas of fabric.
And inifinite lengths tend to be very expensive.

Most other weeds will succumb pretty quickly without any light. Even so
I would hit the entire region with glyphosate first and leave it for two
weeks before installing the membrane. And then add about 8cm of bark
chippings on top for good measure.

Regards,
Martin Brown