"Dover3211" wrote in message


You could always give it a good water to encourage the couch to grow,
and then give it a quick spray with herbicide. It may mean you won't
be able to have your garden bed up and going straight away, but you
will have less grass amongst the plants without having to search
through for all those roots.

Ben

http://www.directedfocus.com.au/gardening

I'd definitely go for this idea, even though in a reply the OP mentioned
water restrictions.
It's the only surefire way to get rid of it, and spray it with roundup
(glyphosphate) mixed at a rate of 100ml, or even 150ml to 10litres of water
and spray EVERY single part of the grass.
The roots and that you mention you left will definitely grow, and once you
get the plants in it will be near impossible to get out, unless you use a
selective herbicide to kill it. One of them is Fusilade, but is very
expensive.
Good luck
Oh, and the weed mat may help with other weeds, but won't work as well on
the couch.