A method of improving turfgrass quality involves applying onto the turfgrass an effective amount of a composition which has been dissolved or dispersed in water, wherein the composition contains between 0.11 and 0.14 parts by weight of a phthalocyanine compound, preferably Pigment Green 7, per one part by weight of monoalkyl esters of phosphorous acid or salts thereof, preferably fosetyl aluminum or salts thereof.