Maryland Code, Agriculture § 6-222

(a)(1) Except as provided in paragraph (2) of this subsection, on or after April 1, 2011, a person may not sell or distribute for use or sale any fertilizer intended for use on established lawns or grass unless it is low phosphorous fertilizer.

(2) This subsection does not apply to organic or natural organic fertilizer that is sold to a professional fertilizer applicator.

(b)(1) On or before April 1, 2011, a manufacturer of lawn fertilizer whose products are sold in the State shall reduce by 50% from 2006 levels the amount of available phosphate (P₂O₅) resulting from the application of its lawn care products within the State.

(2) The amount of available phosphate (P₂O₅) resulting from the application within the State of lawn care products sold or distributed by a manufacturer may not exceed an average of 1.5% available phosphate (P₂O₅) if, prior to April 1, 2010, the manufacturer did not sell or distribute fertilizer in the State intended for use on established lawns or grass.

(3) Beginning in 2011, a manufacturer of fertilizer whose products are sold in the State shall report the pounds of phosphorus in its lawn care products sold at retail locations in the State to the Department at the end of each calendar year.