Mowing Requirements

Begin mowing young grass when it grows above a 2-inch cutting height. Either rotary or reel type mowers may be used but blades must be sharp and reels properly adjusted to prevent pulling up young seedlings. The initial cutting should be at a 2-inch height. Subsequent mowings should be frequent enough so that no more than one-third of the leaf is removed at each mowing. At a 2-inch mowing height the grass needs mowing before it reaches 3 inches. Weekly mowing is usually satisfactory at the 2-inch mowing height. At lower mowing heights more frequent mowing is required. Some of the improved bluegrass varieties such as Fylking, Ram I and Touchdown tolerate mowing heights below 1 inch. However, weaker stands of Kentucky bluegrass result when mowing height is below 1 inch. Also, at mowing heights below 1 inch annual bluegrass and crabgrass invade a bluegrass turf. At mowing heights above 1 inch weeds are much less of a problem.

http://aggie-horticulture.tamu.edu/plantanswers/turf/publications/bluegrass.html