This comes from Paul Otten of the Northland Berry News' website;
http://www.berrynews.com/ :
You've read about various attempts that have been made to use vinegar
(acetic acid), lime sulfur, and other natural products to control or reduce
weeds. In the last issue of Northland Berry News we announced the listing of
the first OMRI organic herbicide, developed right here in our neighborhood,
Eagan, Minnesota, a Minneapolis suburb.
I recently took the opportunity to visit with the father & son team who
make up SummerSet Products leadership: Paul and Bruce Marrs. Both have been
involved in environmentally friendly endeavors for years, so Alldown
herbicide is almost a natural outgrowth of their earlier work, though they
freely credit other researchers with assisting them in refining the product.
Of all the cultural problems organic growers face, especially in the
transition and early years, weed management is certainly one of them.
AllDown will likely prove to be a valuable tool that organic and other
growers will likely add to their weed management toolbox.
Herbicides are normally toxic to humans, the environment and plants.
Alldown is quite different in that it burns back the affected plants or
kills them outright, but does so by a more benign mode: it strips the
protective substances from the leaves and green stems, thus desiccating the
plant. The natural ingredients in the product are not per se toxic. Any
acid, however, no matter its concentration, needs to be used with caution,
kept out of the eyes and other body parts.