Q: A year and a half ago I had a yard man dig up the old shrubs around my house and plant new ones. He assured me that no weeds would come back, but the newly landscaped area is full of weeds and grass I’d like to kill. I have heard that a mixture of vinegar and water will do it safely and not harm animals, but how long must I wait before I can plant anything?
A: Vinegar mixed with water is not a very effective herbicide. It will burn off the leaves of some tender plants but has no effect on weeds with tough roots. You may have heard about University research using concentrated vinegar to kill weeds. The acidic product worked but it is so hazardous and caustic that it can not be sold to homeowners. Household vinegar is 5% acetic acid. The research product was 20% active ingredient, close to battery acid in concentration. In situations where weeds are growing close to flowers, I recommend using a foam paintbrush dipped into diluted glyphosate (Roundup, etc) to “paint” weeds away.