AMES, Iowa – Taking care of an Iowa lawn during the summer can be a challenge. A week of oppressive heat and humidity can be replaced by a week of rain. Rinse, repeat.
With weather changing throughout the summer months, what are the best practices for keeping a lawn healthy and happy?
The biggest thing homeowners can do to keep their lawn happy is simple – mow at the correct height.
“Start with the correct cutting height,” said Adam Thoms, assistant professor and extension turfgrass specialist with Iowa State University. “A proper mowing height is 3 to 3.5 inches, even under dry conditions. If it hasn’t been done already, move your mower height up after mowing shorter in the spring.”
Thoms also recommends never removing more than one-third of the plant’s height during mowing. More information on proper mowing techniques and procedures can be found in the ISU Extension and Outreach publication “Mowing Your Lawn” (HORT 3047).
A lawn receiving the correct amount of water is critical to its long-term health. This can be challenging in the summer when it can be days or even weeks between rain showers.
“Turfgrass needs 1 to 1.25 inches of water in a week to avoid going dormant,” Thoms said. “If watering your lawn, completing that in the morning is always best because watering later in the day can leave the grass wet overnight and heighten its disease risk. Watering during the heat of the day allows too much moisture to be lost to evaporation.”
Keep a close eye on how much watering is being done as well.
“Don’t overwater,” Thoms said. “A lot of people think that if an inch is good two is better, and that’s not true. Too much water can make the roots shallow.”
Summer is also not the time to focus on fertilizing a lawn or applying herbicide. ISU Extension and Outreach publications “Weed Control in Home Lawns” (PM 930) and “Lawn Fertilization” (PM 1057) can provide detailed information about when to apply fertilizer or herbicide.
“Spring and fall are key times for fertilization,” Thoms said. “Excessive growth right now makes tissue likely for disease. Plants are already stressed during the summer and herbicide applications for weed control can lead to burning the turfgrass tissue, especially now when it is already dry.”
Seeding also isn’t recommended during the summer, and publications “Selecting a Grass Species for Iowa Lawns” (HORT 3023) and “Establishing a Lawn from Seed” (PM 1072) can provide additional information.
It also isn’t too early to start thinking about preparing a lawn for winter.
“Aerification of a yard should be done in mid-August to early September to go ahead and relieve summer compaction and allow air to reach the roots,” Thoms said. “Topsoil in most yards isn’t great so it’s a good idea to drag compost into those holes to improve topsoil and water-holding capacity.”
ISU Extension and Outreach publication “Fall Tips to Ensure a Healthy Green Yard in the Spring” (HORT 3021) is full of best practices to ensure a healthy lawn next spring.
PHOTO: Summer heat and water stressed home lawn.