Mowing practices can greatly affect turfgrass health. The two most important factors are mowing height and frequency.
The preferred height of Colorado turfgrass species is two inches to three and one half inches. Grass plants undergo less stress when the amount of blade left on the plant can still function efficiently. Mowing grass to a height of less than two inches can reduce drought and heat tolerance, and cause a higher incidence of insect, disease and weed pest problems. Scalping is never recommended, nor is there any reason to change mowing heights during the year.
Mow the lawn frequently enough so that no more than one-third of the grass blade is removed during a single mowing. This requires changing your mowing schedule to reflect how quickly the grass grows. This can range from four to ten days between mowing. Bottom line: keep mowing ‘til’ the lawn stops growing.
Clippings left on the lawn can be beneficial to the plants and save mowing time. Clippings break down quickly, which allows nitrogen and other nutrients to be recycled. Clippings can also encourage the growth of beneficial soil microorganisms. Studies show that it takes less time to mow more often and leave clippings on the lawn than to mow less often and catch and bag clippings for disposal.
Mowing equipment should be well maintained. Sharpen blades after every third mowing, or, at the least, once a month.
For more information, see the following Colorado State Extension fact sheet(s).