Pre-emergents and most post-emergent herbicides will suppress or damage desirable seed. If we’re overseeding, we avoid those products for a window before and after service; instead, we rely on mowing height and hand removal until seedlings are mature. As a rule of thumb, wait until you’ve made three to four mowings on new grass before broadleaf spraying resumes. If weed pressure is high, we’ll design a seed-safe strategy and revisit selective control once the stand is established.