Maryland Fertilizer Law


Nutrients—primarily nitrogen and phosphorus—are key ingredients in lawn fertilizer. When it rains, excess nutrients can wash off the land and into the streams and rivers that feed the Chesapeake Bay. Once in our waterways, excess fertilizers contribute to the growth of algae blooms that block sunlight from reaching Bay grasses, rob the water of oxygen and threaten underwater life.

Montgomery County does not directly regulate fertilizer usage, but the County abides by the rules set by state law. 

Be Wise: Don't Over-Fertilize

The Maryland Fertilizer Law limits the amount of nutrients that can be applied to lawns or turf and restricts phosphorus content in lawn fertilizer. The goal is to help homeowners and lawn care professionals maintain healthy lawns without applying unnecessary amounts of nitrogen and phosphorus.

  • Read and Follow all label instructions

  • Do not fertilize if heavy rain is expected

  • Keep fertilizer away from streams, sidewalks and driveways

  • Don't fertilize between November 15 and March 1

  • Hire only certified professionals to fertilize lawns


Homeowners and do-it-yourselfers are required to follow University of Maryland recommendations when fertilizing lawns. Mandatory restrictions, similar to those imposed for lawn care professionals, apply.