On 12/08/2018 14:31, Jim S wrote:
My daughter in law has turned over an old lawn which has had Evergreen 4 in
1 on it. Is it safe to plant/sow edible crops on the plot?

A quick and dirty test for any soil is will mustard & cress grow on it
without showing distortion of growth. If it grows OK then the weedkiller
has largely become deactivated or passivated by the soil.

Evergreen 4 in 1 doesn't contain anything too terrible. Something to
kill broadleaf weeds and moss and a bit of superphosphate.

https://www.lovethegarden.com/system...1%20015013.pdf

There are some commercial farm weedkillers that are incredibly
persistent and can be present in horse manure. There was an issue with
it a couple of years back causing trouble on allotments.

--
Regards,
Martin Brown