The sun is shining, the humidity is falling and the temperatures are rising. With our summer staying hot and in the triple-digits, it is no wonder that our landscapes, and especially our lawns, are starting to look worse for wear.
Summer is a challenging time for knowing the proper way to care for our lawns. Many people see shades of blue-grey and then brown and assume their turf needs fertilizer or has a disease. In most cases, fertilizer is not the solution, nor is disease the cause.
Kentucky bluegrass is the most commonly planted grass in our area, and it is a cool-season grass. Cool-season grasses preform best in winter and spring when temperatures stay below 85 degrees. When Kentucky bluegrass does not receive adequate moisture or becomes stressed by heat in the summer months, they have a tendency to go dormant, or brown, until conditions improve in fall.
While symptoms may look like a disease, in most cases this is not the problem. Common infectious turfgrass diseases are caused by plant pathogenic fungi, like leaf spot or melting out, and require long periods of dew on the leaf blades and warm evening temperatures. In northern Nevada, we typically have low humidity which reduces the likelihood of diseases in most lawns. Taking into account the lack of thunderstorms this summer and our naturally low, and now extreme low, humidity, most diseases will not have the conditions needed to grow.
Now it is time to look at our maintenance practices and moisture. This year, I have seen several grass samples come into the office showing cuts from dull mower blades. If your mower’s blades have not been sharpened, your mower will rip your grass. This causes turf to lose more water through its leaves and appear tattered with straw colored tops.
If you have areas of bright green under the shade of trees and areas of brown where the lawn receives full sun, it is time to look at your watering practices. To determine how much moisture your lawn receives and how evenly it is irrigated, “can your lawn.” Place straight-sided coffee cups or soup cans throughout turfgrass areas. Run your irrigation system, allowing water to collect in the containers. Then, measure the water caught. Detailed instructions are available online at growyourownnevada.com/can-test-sprinklers. Check soil moisture with a resistance test using an eight or twelve inch screwdriver. Dry soil will be difficult to get the screwdriver into whereas moist soil will be much easier to penetrate. The Washoe County evapotranspiration website, washoeet.dri.edu, can give you an idea of how long to water given your sprinklers and current weather conditions. These figures will need to be modified for your yard and soil type.
To keep your lawn beautiful, water deeply to maintain a root system at least 6 to 8 inches deep. Avoid early evening watering during the hot summer months to reduce the possibility of disease. Wait to fertilize until conditions are cooler and the lawn has appropriate moisture to support new growth. Keep mower blades sharp and mow high, at least 3 inches.
Wendy Hanson Mazet is a horticulturist and certified arborist with University of Nevada Cooperative Extension. Have questions about your plants? Contact a Master Gardener at 775-336-0265 or firstname.lastname@example.org, or visit www.growyourownnevada.com.