Vinegar as an Herbicide?

After a wet spring, many of us are doing nothing else but battling obnoxious weeds. In the past, I have often been asked about using vinegar as a weed killer. I really couldn’t recommend a home remedy, because it wasn’t scientifically based information whose toxicology and effectiveness had been thoroughly tested.

There is a newly approved herbicide containing 20 percent non-synthetic acetic acid, the main component in vinegar – although regular vinegar contains approximately 5 percent acetic acid. This weed killer has been approved for organic crop production by the USDA Organic program. The label of the product lists it as “a horticultural biopesticide for nonselective control of herbaceous broadleaf weeds and weed grasses which surround food crops, non-food crops and non-production agricultural, farmstead, right of way, and institutional land sites.” The label also states that the product affects all contacted vegetation, whether desirable or undesirable. For example, application to lawn weeds can kill the grass too.

I’m not advocating this pesticide – yes, herbicides are pesticides whether or not they are organic – but rather pointing out that just because something is listed as organic, “Mother Nature is meaner than you think” (Dr. Allan Felsot, Washington State University). The Material Safety Data Sheet (MSDS) required on all products – including household cleaners and office supplies – states that this pesticide’s vapors are irritating to the eyes and respiratory tract. Avoid inhalation. Liquid may cause eye burns and permanent damage to cornea, possibly leading to blindness. The product causes skin irritation.

This newly certified acetic acid product for organic production carries a DANGER warning, the highest hazard rating for a pesticide. The label states: “corrosive – causes irreversible eye damage. Wear goggles or face shield when handling. Harmful if absorbed through the skin.” A National Institute for Occupational Safety and Health-rated respirator is listed as a required piece of personal protection equipment. The product is toxic to birds, fish and aquatic invertebrates. Respirators must be custom-fitted to your face to function properly.

For any pesticide, organic or not, always read and follow the label, carefully.

On Saturday June 25, 11:00 at Rail City Nursery in Sparks, Master Gardeners will talk about invasive exotic beetles such as emerald ash borer, Asian longhorned beetle and more. Find out about these problem pests to keep our landscape and forest trees safe.