ANNAPOLIS (November 21, 2017) The Maryland Department of Agriculture reminds citizens that fertilizer blackout dates authorized by Maryland's Lawn Fertilizer Law are now in effect. The law prohibits citizens and lawn care professionals from fertilizing their lawns with products containing phosphorus and nitrogen between November 16 and February 28. An exception exists for lawn care professionals who may apply nitrogen to lawns that they manage until December 1, using specially formulated products that reduce the risk of nutrient runoff into streams, rivers and the Chesapeake Bay. Potassium and lime may still be applied during the blackout dates since they are not considered a threat to water quality. Both citizens and lawn care professionals may resume lawn fertilizer applications containing nitrogen and phosphorus on March 1, as long as the ground is not frozen or heavy rain is not predicted. As an additional reminder, fertilizer may not be used to de-ice walkways or other impervious surfaces.

Maryland's Lawn Fertilizer Law requires both homeowners and lawn care professionals to follow University of Maryland fertilizer recommendations and use best management practices when fertilizing lawns. In addition, the law requires lawn care professionals to be licensed and certified by the Maryland Department of Agriculture to apply fertilizer to the properties they manage. The department maintains a list of certified lawn care professionals along with additional information on Maryland's Lawn Fertilizer Law on its website at