On the plots we throw and mow, we don’t spray we just spread and then bush hog. Usually plant in the first 10 days of October and it works just fine. At that point in the season, weed regeneration doesn’t occur and if it does the cooler weather slows the growth until the first frost occurs. We are in SE Alabama. 10 years ago we could have done this in late September but seems the heat hangs on for longer now, so early October works best.