District of Columbia Code Division I. Government of District. § 8-104.03. Fertilizer application requirements.

(1) Beyond a 15-foot buffer area from a waterbody; provided, that fertilizer may be applied beyond a 10-foot buffer area if a drop spreader, rotary spreader with a deflector, or targeted spray liquid is used for the fertilizer application;

(2) When sufficient water is applied to the soil within 24 hours of application to immobilize the fertilizer and prevent fertilizer loss by runoff or when soil is sufficiently saturated to immobilize the fertilizer and prevent fertilizer loss by runoff;

(3) When a heavy rainfall is not occurring, and when soils are not saturated and the potential for fertilizer movement off-site exists;

(4) After March 1st and before November 15th in a calendar year;

(5) When the ground is not frozen; and

(6) In an amount consistent with an annual recommended rate established by the Department.

(d)(1) A fertilizer that contains phosphorus in an amount greater than 0.67% phosphate by weight may be applied to turf only according to paragraph (2) of this subsection.

(2) A low phosphorus fertilizer may be applied to turf if a soil test conducted within the previous 3 years indicates that the level of phosphorus in the soil is insufficient to establish, reestablish, repair, or support adequate turf growth; provided, that a fertilizer that contains phosphorous other than a low phosphorus fertilizer may be applied to turf if the soil test indicates that the level of phosphorus in the soil is insufficient to establish or reestablish turf. The application of fertilizer allowed under this paragraph shall not exceed the amount or rate of application of fertilizer recommended by the soil test, as determined by the Department.

(e)(1) A fertilizer containing nitrogen may be applied to turf only at an application rate of less than 0.7 pounds per 1,000 feet of water-soluble nitrogen, and at an application rate of less than 0.9 pounds per 1,000 square feet of total nitrogen.

(2) Notwithstanding paragraph (1) of this subsection, an enhanced efficiency fertilizer containing nitrogen that has a release rate of less than 0.7 pounds per 1,000 square feet of total nitrogen per month may be applied at an annual application rate of less than 2.5 pounds per 1,000 square feet of nitrogen. The annual total application rate may not exceed 80% of the annual recommended rate for total nitrogen, as established by the Department.

(3) A fertilizer containing nitrogen may be applied to turf only if the fertilizer is at least 20% slow release.