On 29/04/18 09:31, David wrote:
On 29/04/2018 06:37, Chris Hogg wrote:
On Sat, 28 Apr 2018 22:52:20 +0100, Tim Watts
wrote:

If you do the "cover some ground with a blackout sheet" thing, how long
should you leave it at this time of year to kill everything?

I have an uncared for raised bed and the kids would like to own it for
some flowers and stuff. Rather than nuke it with glyphosate, I have some
scrap DPM sheet (heavy black plastic).

I just wondered how long?

Depends on the type of weed and time of year. In spring/summer,
perhaps only a couple of months, but at least twice as long in winter.
Deep-rooted weeds may also survive a lot longer than shallow rooted
ones. DPM should be fine, but thin stuff like black bin-liner might be
just let enough light through not to be effective. Weight the plastic
down with stones, bricks or just earth to stop it blowing around.

Glyphosate is quicker.

Or just dig it over, no chemicals and ready to use once done.

And if he has ground elder, horsetail, bindweed, creeping buttercup, etc
, etc is that still the advice you would give?

--

Jeff