Q: If I have been using wheat straw to mulch around my vegetable plants. Will the chemicals that may have been used on the wheat crop affect my vegetable plants? Things just don’t seem to be growing as vigorously as in previous years.
A: It is certainly possible for weed killers sprayed on wheat straw to affect vegetables but the symptoms are quite noticeable. Leaves thicken and twist and look very unnatural. My bet is that you don’t have a problem with herbicides but with nutrients. We’ve had so much rain this year that unless you have fertilized your vegetables regularly they may simply be suffering from lack of fertilizer. Use a water soluble fertilizer on your garden and see if things perk up in a few days. If so, wait two weeks and fertilize again.