Granular pre-emergence herbicides can help manage winter weeds in the lawn when applied prior to weed germination. Pre-emergence herbicides containing pendimethalin (Scotts Halts), dithiopyr (Hi-Yield Weed Stopper), and benefin plus trifluralin (Green Light Crabgrass Preventer) provide good control of annual bluegrass, common chickweed and various other winter annuals prior to their emergence. Isoxaben (Green Light Portrait) provides good control of winter annual broadleaves. Isoxaben has no activity on germinating grasses, so consider applying one of the previously mentioned herbicides on the same lawn for a complete broad-spectrum, pre-emergence weed control program.
Pre-emergence herbicides should be applied by mid-November. Water the herbicide into the lawn or apply just prior to rainfall. Make sure you use pre-emergence herbicides that do not contain nitrogen fertilizer because of potential for increased occurrence of brown patch disease.