AMES, Iowa — Proper mowing practices play a vital role in helping to maintain a healthy, sustainable home lawn. Horticulturists with Iowa State University Extension and Outreach answer questions about lawns and lawn mowing. Homeowners and gardeners with lawn questions should contact horticulturists at Hortline by emailing firstname.lastname@example.org or calling 515-294-3108.
What is the proper mowing height for a lawn?
Kentucky bluegrass lawns should be mowed at a height of 2.5 to 3 inches in the spring and fall months. Mow bluegrass lawns at a height of 3 to 3.5 inches in June, July and August. A higher mowing height in summer helps to cool the crowns of the turfgrass plants, encourages deeper rooting and provides more leaf area for photosynthesis during the stressful summer months.
Mowing below the recommended range may scalp the turf and cause the turfgrass to deteriorate. Low mowing heights make the turfgrass more susceptible to drought, high temperature and wear injury. In addition, low mowing heights increase the likelihood of weed problems.
Mowing too high reduces tillering and causes matting of the grass. Reduced tillering results in fewer and coarser plants. Matted grass creates a micro-environment that encourages disease development.