Acetic Acid (Vinegar) for Weed Control
It seems that many have heard something about using vinegar
for weed control this summer. It has been in the popular press
and on the internet so we were not surprised that several people
asked about it last week at Farm Progress Days. The same must
be happening in Iowa as Micheal Owen, an ISU weed scientist
prepared an article for their Integrated Crop Management
Newsletter. We thank Dr. Owen for permission to use his
article; his efforts saved me the time of doing an article on
this topic. Here is a slightly edited version what he wrote in
the July 15 issue of their newsletter.
As a result of questions regarding the use of vinegar as a
tool for controlling weeds, I contacted the USDA researchers
that conducted the work and also checked a number of sites on
the Web for information. The information below is from
discussions with the researchers Dr. John Teasdale and Dr. Jay
Radhakrishnan, and publicist Don Comis, and is reported at
several web sites (www.barc.usda.gov/anri/sasl/vinegar.html
and http://www.ars.usda.gov).
It is important to recognize that the use of acetic acid
(vinegar), unless the material is specifically labeled as a
herbicide, is illegal and a violation of FIFRA. A number of
companies have registrations for acetic acid to be used as a
herbicide. This information can be accessed at
www.garden‑ville.com,
www.greensense.net,
www.bradfieldind.com,
and www.biconet.com.
Various lawn and garden stores may carry these products.
Like any herbicide, it is important to follow all directions and
safety procedures. The USDA issued a warning in their research
report stating: "WARNING: Note that vinegar with acetic acid
concentrations greater than 5% may be hazardous and should be
handled with appropriate precautions.” However, acetic acid is
not reported to accumulate in the environment and readily breaks
down to water.
Acetic acid is not a selective herbicide. Dr. John Teasdale
suggested the mechanism of action of acetic acid is similar to
that of paraquat in that acetic acid causes the rapid
dissolution of cell membrane integrity resulting in the
dessication of foliar tissues, and ultimately plant death.
Acetic acid is non‑selective, and may damage any plants
contacted by the material.
While acetic acid may burn off the tops of Canada thistle and
other perennials, it will not control the root system
responsible for regeneration of plants. Furthermore, a recent
demonstration at the Nashua Research Farm suggested that acetic
acid is not effective at controlling larger weeds.
Directed applications (keeping the vinegar away from the crop
plant) are necessary to use acetic acid when crops are present
in fields. Acetic acid concentrations from 10 to 20% controlled
80 to 100% of the smaller weeds, as reported in the USDA
release. Typical concentration of acetic acid in most
commercially available vinegars is 5%, and this concentration is
reported to provide variable control of small weeds.
The USDA researchers suggested the spot spraying at the base
of corn might be the most effective manner to utilize acetic
acid as a herbicide. Broadcast applications of 20% and 30%
acetic acid solutions would cost approximately $66 to $99 per
acre, respectively. Banded applications could reduce that cost
to one third of the broadcast rate.
July 2002 |
