Many home gardeners and farmers experiment as often as scientists do. But as valuable as the gardeners' and farmers' experiments are, their results are usually called "folklore," not science.
Gardeners and farmers often want scientists to test their folklore, to see if it really works. That's what happened with organic farmers and gardeners who discovered that common household vinegar kills weeds.
These individuals started using vinegar instead of chemical weed killers--and recommending it to friends. Not all of the gardeners and farmers were entirely convinced, though, and some had questions that the scientists could best answer. Like, would vinegar ruin the soil because it is such a strong acid?
Three Agricultural Research Service (ARS) weed scientists in Beltsville, Maryland--Jay Radhakrishnan (formerly ARS), John Teasdale, and Ben Coffman--decided to do scientific experiments to find out.
They knew that if it worked, vinegar would be great for farmers and gardeners who choose not to use most weed-killing chemicals, called herbicides.
They tested vinegar on five major weeds. One of these was Canadian thistle.You may have noticed it growing on the side of the road or in your own backyard around walls or the patio.
In a greenhouse, the three scientists hand-sprayed the thistle with different mixtures of vinegar. Typical white vinegar bought from the store was the weakest mixture--95 percent water and about 5 percent vinegar.