JoAnne Skelly: Is vinegar a safe alternative herbicide?

A reader recently asked me if a solution of vinegar, Epsom salts and a small amount of liquid dish soap, mixed and sprayed on weeds was as effective as using glyphosate (the active ingredient in Roundup and similar products) and safer. The reader went on to ask, “If this solution is as effective as Roundup and much cheaper, is there anything in the mixture that would/could be dangerous to humans?” Yes, vinegar (acetic acid) can be hazardous. For example, according to University of Maryland E