Q: Is it safe to use grass clippings from a chemically treated lawn as mulch for other plants?
—Jamelle, Elkins, West Virginia
A: Roger Cook replies: Because I have no definite proof that you can, I would recommend that you don't. I worry that the herbicide on the grass could release into the soil as the grass breaks down and be picked up by other plants.
However, if you're not treating the lawn with chemicals, grass clippings do make a great mulch.