Mr. Weedy says: Whatever you use, it’s important to know when and how to apply a weed control. It is best to apply weed controller about a month before the weeds you get germinate and surface. It is important to remember that rain can severely reduce the effectiveness of a weed controller if it falls soon after application. Try to pick a week with little rain fall. Contact Weed Pro Lawn Care directly for help with your landscape projects. Additional reference sources include organic lawn treatment georgia or norcross lawn care.