On 13/11/2014 09:46, Martin wrote:
On Wed, 12 Nov 2014 18:51:38 -0000, "Bob Hobden" wrote:

"Charlie Pridham" wrote


"Broadback" wrote
, SecondFromLeft wrote:
I have recently taken on a large allotment which has a severe case of
couch grass invasion. Could someone please tell me the best thing to
cover the area with whilst I am working on other parts of the
allotment.

If I can help it I do not want to use any weed killers. I have read
covering over is one of the better solutions.

My two thoughts of covers are a think black plastic polythene sheet
Something like : ('HEAVY DUTY BLACK POLYTHENE PLASTIC SHEETING 4M WIDE
DPM ROLLS 300MU 1200 GAUGE | eBay' (http://tinyurl.com/nr4csbh))

With option two being heavy duty garden control fabric. Something like :
('Kenley Garden Landscape Weed Control Fabric Ground Cover - Heavy Duty
100GSM | eBay' (http://tinyurl.com/lewfp78))

Does anyone have any preference over these two options or am I missing
something better on the market.

Depends on you budget. The cheapest option is to go to a carpet retailer
and ask them for a bit of rubbish carpet, then place that over. The
trouble with the black polythene, especially the thin variety is that
winds will soon wreck it.

Carpet is also better as it allows water through

In my experience seen on another allotment site it also lets the Couch Grass
through then you have old carpet stuck to the ground with couch and
virtually impossible to remove! How long does couch have to be covered to
kill it, one whole season or two? Then there is the problem of what
chemicals etc are on the old carpet, no way of telling, and do you want them
in your soil if you are so nervous about such things.

Why not use Glyphosate, IME it is the only sure way to rid your plot of
couch grass which is even worse than bindweed for coming up again from any
small bit of root left in the soil. One or maybe two applications should
kill it completely and you can then dig in the dead weed and know you have a
clean plot. Then you can use your whole plot next season and only have to
concern yourself about it coming back from the surrounding area. A quick
squirt of Glyphosate around the edge once a year will see to that too.
Most of us on our site use it to keep our rabbit fences clear of weeds so we
can see where the little blighters are trying to dig in.

You can buy a membrane that is opaque, but water permeable. Using this it takes
at least a year to kill the couch grass under the cover. You need to kill the
couch grass on a strip of land along the edge of the cover first otherwise the
couch grass under the edge of the membrane grows outwards towards the light.
Use glyphosate while you can, before it is banned. From 1 January 2015 in the
Netherlands there will be a ban on the use of glyphosate, except for
agriculture. In particular local authorities and private individuals are banned
from buying and using it. It was found that glyphosate applied to roads and
pavements by local authorities was sometimes being washed down the drains by
rain before it had time to break down.

Even if that is true the LD50 for glyphosate is about the same as that
for the caffeine in coffee. The surfactants (aka washing up liquid like
compounds) added to the commercial formulations are far nastier.

This is an example of the irrational fear of chemicals resulting in a
stupid decision when all that is needed is some training of the
operatives not to spray when rain is expected and to be selective.

--
Regards,
Martin Brown