Summer Care of Lawns

Sound mowing practices are necessary to obtain a good quality lawn. This is especially true during the summer months. Improper mowing during hot, dry weather may seriously damage the turf. Kentucky bluegrass lawns should be mowed at a height of 3 to 3 ½ inches during the summer months. (During cool weather in spring and fall, bluegrass lawns should be mowed at a height of 2 ½ to 3 inches.) The additional leaf area during summer shades and cools the crowns of the turfgrass plants. Extremely high temperatures at crown level can kill turfgrass.

When mowing the lawn, never remove more than 1/3 of the total leaf area at any one time. Accordingly, a lawn being mowed at a height of 3 inches should be cut when it reaches a height of 4 ½ inches. Removing more than 1/3 of the leaf area weakens the turfgrass and reduces its capacity to withstand additional environmental stresses. Weakened turf is also more likely to be invaded by weeds.

If possible, mow in the cool of the morning or evening. Mowing at midday may place additional stress on the turf. Also, make sure the mower blade is sharp. Dull blades tear and bruise the leaf tips.

Gardeners have two basic options on lawn care when confronted with hot, dry weather. One option is to simply allow the turf to turn brown and go dormant. The alternative is to water the turfgrass to maintain a green, actively growing lawn.

Kentucky bluegrass lawns can survive extended periods of drought by going dormant. Most healthy lawns can survive in a dormant state for 4 to 6 weeks without rainfall or irrigation. Healthy lawns that have been allowed to go dormant will green up again when the turf receives sufficient water.

Gardeners who want a green lawn throughout the summer should begin to water the lawn when symptoms of moisture stress begin to develop, but before the grass becomes dormant. A good indication of water stress in turfgrass is leaf color. The normally green leaves become a dull blue-green. Additionally, water-stressed turfgrass is less resilient. Footprints remain in the turf after walking across it.

Turfgrass requires approximately 1 to 1 ½ inches of water per week. (The actual amount of water required is largely dependent upon soil type and weather conditions.) When irrigating turfgrass, the general rule is to water deeply, but infrequently. A thorough soaking (which moistens the soil to a depth of 6 to 8 inches) once a week is much better than frequent, light applications of water. Deep watering promotes the development of deep, extensive root systems. Deeply-rooted turfgrass plants can withstand stressful weather conditions much better than shallow-rooted plants.

Sprinklers are the best way to water lawns. The amount of water applied may be determined by placing 2 or 3 rain gauges within the spray pattern.


Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on June 6, 2007. The information contained within may not be the most current and accurate depending on when it is accessed.