Sep 29

Vinegar vs. Herbicides

Posted on September 29, 2021 at 8:19 AM by Alicia Doran

Recently on social media sites we have been seeing a lot of people touting the use of Acetic acid (a.k.a. Horticultural Vinegar) as a substitute for 'traditional' herbicides.  Many people are unaware of the truth about Acetic acid and mistakenly think it is the same as the vinegar you put on your salad.

  • Horticultural vinegar is a 20-30% solution of Acetic acid (salad vinegar is 5%)
  • Acetic acid is highly corrosive and can cause severe and permanent eye injuries including blindness.  It also is caustic to skin and can cause long-term respiratory problems.


  • There are some Acetic acid products labeled as herbicides.  Not all sites may be listed on the label.
  • The labels list required personal protective equipment (PPE) including eye protection, N-95 respirators, gloves, long sleeves, long pants, shoes plus socks vs. some traditional herbicides that are less restrictive and may only require long sleeves, long pants, and shoes.
  • The products have a 'Danger' label meaning that they pose a health and/or environmental risk vs. many common herbicides that are lower risk and have a 'Warning' or 'Caution' label. (Yes - Including glyphosate which usually has a Caution label).
  • Some Acetic acid products prohibit reentry into an area (including non-ag sites) for 48 hours.  Most traditional herbicides allow reentry into non-ag sites once the spray has dried.
  • Not all acetic acid products are labeled for herbicide use.  If they are not labeled for herbicide use on your site, it is illegal to use them.

Activity and Effectiveness

  • Acetic acid works best on young, newly emerged annual or biennial plants on warm and sunny days.
  • Acetic acid will kill young foliage but DOES NOT move within the plant.  It is not effective for controlling deep-rooted perennial plants like Canada thistle or Dalmatian toadflax.  While it may damage the leaves, it will not kill the roots and the plants will survive and regrow.

Learn More

University of Maryland

Sep 16

Fall Weed Control

Posted on September 16, 2021 at 7:05 AM by Alicia Doran

Common mullein rosette.

Fall is one of the best times to manage your noxious weeds.  For perennials like Canada thistle, Dalmatian toadflax, and Leafy spurge, fall applications of herbicide are very effective as the plants begin to move resources to the roots.  Target both the established plants and any newly emerging seedlings.

Fall is also the time to get a head start on managing your biennial weeds like Musk thistle, Diffuse knapweed, and Common mullein.  Focus on the newly emerging rosettes.  They can either be removed (including the top couple inches of the root) or treated with herbicide.

By working this fall, you can significantly reduce the number of weeds next spring.  

Aug 25

Fall Stewardship Webinar Series

Posted on August 25, 2021 at 3:55 PM by Alicia Doran

Fall Stewardship

Jeffco ISM and CSU Extension (Boulder, Jeffco, and Larimer Counties) are hosting a 4-week speaker series from Sept 15 through Oct. 6.

Join us for talks that will educate and inform landowners on land stewardship for small acreages and the latest trends. 

Free – Register at

Sessions will be held virtually from 6:00–7:30 pm 

September 15

Dryland Pasture Management - Joe Brummer, CSU Dept. of Soil and Crop Sciences

September 22 

Fall Noxious Weed Management - Joe Swanson, Boulder County Parks and Open Space

September 29

Living With Wildlife - Mary Ann Bonnell, Jefferson County Open Space

Protecting Your Livestock - Sharon Bokan, Boulder County CSU Extension

October 6

Forest Stewardship - Nate Beckman, CSFS Golden District