According to University of Maryland Extension Service, November 15 is the cutoff date for homeowners to fertilize their lawns in the fall. According to Maryland’s Fertilizer Use Act that went into effect in 2013, you may not apply lawn fertilizer between November 15 and March 1.
The law also prohibits lawn fertilizer applications within 10 to 15 feet of waterways. These restrictions are intended to help protect the Chesapeake Bay from excess nutrient runoff.