In message , Rodger Whitlock
writes
On Mon, 2 Aug 2004 16:54:12 +0100, dirt dibbler wrote:

Entirely aside from the weeds you see (and their roots below
ground), the soil in your allotment is heavily laced with weed
seeds. These will cause endless work as they germinate.

There are generally so many weed seeds in the ground with long latency
that you will never get rid of them.

So, in
addition to killing such weeds as are already growing, it would
be desirable to eliminate or reduce the numbers of weed seeds in
the soil.

You can only do this by attrition. Regular hoeing is as good a way as
any and preventing any seed heads on existing weeds. You cannot do much
about all the wind blown seeds arriving in vast numbers..

Unfortunately easier said than done!

I've read of several methods:

One, use a pre-emergent weedkiller like simazine; this kills the
young weed seedlings just as they germinate. I do not know if
simazine is still available.

Bad idea. Nothing else will germinate in the soil. I once knew someone
who had problems with holes in their lawn caused by using this stuff
irresponsibly. I certainly would not use anything so nasty and
persistent on ground that I intend to grow fruit and vegetables on. On
the paths maybe as a last resort.

Two, leave the ground fallow for a season, water it, fertilize,
and hoe it regularly. This encourages the weed seeds to germinate
and then destroys them.

There are so many weed seeds that the moment you turn over the soil
light activates a whole bunch more. There are plants whose seeds
specialise in lying dormant almost forever in soil until they get a
chance at the surface.

Three, cover with *clear* plastic and let solar heat sterilize
the soil. I don't know if the UK is sunny enough for this to
work,

We call those poly tunnels over here. It might allow the weeds to get a
better head start in spring, but it would never heat them up
sufficiently to kill them. We seldom get really warm cloud free sunny
days.

Regards,
--
Martin Brown