On Jul 26, 9:55 am, Martin wrote:
On Wed, 25 Jul 2007 16:14:25 -0700, "

wrote:
On Jul 25, 11:02 pm, "Bob Hobden" wrote:

Inactive on contact with soil, are you sure?

I am "pretty" sure Bob as we use it.

It has to make contact green parts of the plant to have an effect.
Some extremely waxy plants like holly seedlings can resist it
(although this is not something to depend upon). After two weeks it is
fully replantable even for seedlings. I have never had any
difficulties with it at all. It is extremely lethal to plants and
relatively benign in animals (although the wetting agents used in real
formulations are pretty bad).

Try growing mustard & cress seedlings to test for weedkiller residue -
it is a sensitive test.

And don't buy Monsantos Roundup unless you like their GM monopoly, buy
the cheaper generic Glyphosate own brand with the highest proportion
of active ingredient per £.

It becomes inactive/breaksdown after some time.

http://answers.google.com/answers/threadview?id=508121

It is to all intents and purposes inactivated physically by adsorption
on contact with normal soil (unless you live somewhere with very free
draining pure sand). The glyphosate decomposes completely over a few
weeks under normal conditions in the UK. In a US arid desert all bets
are off.

Regards,
Martin Brown