acetic acid as safe herbicide
We would like to use a natural herbicide in the course gravel of our perennial program nursery to help control weeds as they emerge. We would like to use white vinegar (household strength, not 20%), mixed with water and a few drops of Dawn as a surfactant. A small test area proved to be very effective. The spray area would be limited to direct contact with emerging weeds. Is this considered a safe product for us to use?
The acetic acid concentration for herbicidal use should be about 15 to 20%. Household (food-use) vinegar is about 5% acetic acid and isn't effective for controlling most weeds. Acid solutions are believed to cause changes in plant cell pH that result in loss of cell membrane integrity and eventual death. Alternatives to synthetic herbicides include natural chemicals, such as acids, soaps, oils, and salts that can act as contact herbicides. These nonsynthetic herbicides are best used as a targeted spray or in noncrop areas because contact can damage plants in production. It is important to note that these products do not kill roots, and repeated applications will be necessary for weeds that have the ability to regenerate from their roots.
Here are two publications you may find useful.
Hope this helps!