How soon I can plant my edibles after I’ve used weed and
feed?
Do you know which weed and feed product was used? That would help in
determining the chemical’s half life (persistence) in the soil. Regardless of which chemical was used, my
recommendation would be not to plant any edibles in a site which has been
treated with weed and feed, but to find another location for your food
plants (such as containers made of safe materials, or raised beds with a
barrier between the bed and the chemically treated area of the garden).
Local garden writer Ann Lovejoy has discussed weed-and-feed products in
her column. Here is a link.
Here is what retired Washington State University Extension agent Mary
Robson had to say on this subject in one of her columns no longer available online:
Just one note of caution-be careful with all chemicals. Many pesticides
ordinarily used in gardens are not allowed on edibles. An example is Lawn
Weed and Feed which will harm any broadleaf plant whether lettuce or
marigold or petunia. It’s probably safest to keep pesticides out of the
garden if you plan to eat the produce.
Formerly available from the website of Washington Toxics Coalition:
The Hazards of Weed and Feed
“Weed and feed is a mixture of lawn fertilizer with weed killer, usually
2,4-D and related compounds. The problem with weed and feed is that it is
designed to be applied to the entire lawn regardless of whether or not
weeds are actually present. This encourages over use. For example, if 30%
of your lawn is covered in weeds, 70% of a weed and feed application will
be wasted, since the herbicides have no residual action. Since many
people do not realize that weed and feed is a pesticide, they may be less
inclined to read an follow label instructions. For example, did you know
that it is illegal to apply weed and feed more than twice per year on the
same site?
“The herbicides in most weed and feed products are mobile in soils and are
widely found as pollutants in local streams, according to the U.S.
Geological Survey. In addition, 2,4-D is neurotoxic and may be a
carcinogen according to some studies.
“Weed control should be practiced only as needed, not every time you
fertilize. Mechanical controls are preferable to protect health and the
environment. If chemical controls are used, spot treatment should be
utilized to minimize product use and resultant risks from direct exposure
and track-in to the home on shoes and feet.”
Here are links to information on some common weed-and-feed type products
and their hazards:
From the Pesticide Action Network North America
From the Winter 2005 (updated April 2006) article in Journal of Pesticide Reform