The government requires all lawn care services for hire to post these flags. No matter what treatments we apply to your lawn we must post this flag. Even if you were to hire a company to water your lawn with a water truck when you go on vacation, a flag would need to be posted by law. If you notice, the mandatory wording says to “stay off the grass till treatment dries”. We must post this flag by law even when applying a dry, granular fertilizer treatment.