The number of weeks a lawn requires regular mowing is not a fixed annual figure, but a variable. The mowing season can range dramatically from less than 20 weeks in northern climates to 40 weeks or more in southern regions. The primary factors dictating this range are the specific type of grass planted and the sustained soil temperatures that stimulate or halt its growth.
How Grass Type Determines Season Length
Turfgrass is broadly categorized into two major types, and the one established in your yard fundamentally shifts your mowing calendar. Cool-season grasses, which include varieties like Kentucky Bluegrass, Tall Fescue, and Perennial Ryegrass, thrive in cooler temperatures. These grasses exhibit two peak periods of vigorous growth: one in the spring and another in the fall, separated by a slowdown during the summer heat.
This dual-peak growth pattern means that cool-season grasses may require mowing for 30 to 40 weeks in regions with mild winters and extended spring and fall periods. Conversely, warm-season grasses, such as Bermuda, Zoysia, and St. Augustine, are built for heat and go completely dormant when cold arrives. Their growing season is typically shorter and more defined, generally lasting between 20 and 30 weeks, as they stop growing entirely during the winter months.
Identifying the Start and End of Your Mowing Window
The precise start and end dates of the mowing season are determined by sustained soil temperatures, which act as the biological signal for grass to begin or cease active growth. Mowing begins when the soil temperature consistently reaches 50 to 55 degrees Fahrenheit, a threshold that signals the “go time” for cool-season grasses. Warm-season grasses require a higher sustained soil temperature, typically needing the ground to reach 65 degrees Fahrenheit before they fully wake up and begin pushing out new blades.
The end of the mowing window is often dictated by the average first frost date, which serves as a hard boundary. Warm-season grasses enter dormancy when soil temperatures drop below 50 to 55 degrees Fahrenheit. For cool-season varieties, upward growth slows significantly and eventually stops when soil temperatures consistently fall below 45 degrees Fahrenheit. Local agricultural extension offices often provide historical first and last frost dates, offering practical data for homeowners to estimate the boundaries of their growing season.
Mowing Frequency Based on Seasonal Growth
Once the growing season is established, the frequency of mowing is not constant but fluctuates with the grass’s growth rate. The season typically begins with a period known as the “Spring Flush,” where rapidly warming soil and ample moisture cause an explosion of growth. During this time, it may be necessary to mow every five to seven days, or even more frequently, to adhere to the rule of never removing more than one-third of the grass blade height in a single cut.
Mid-summer often brings a slowdown in growth, particularly for cool-season grasses that enter a semi-dormant state due to heat and drought stress. Mowing frequency may drop during this period, sometimes only requiring attention every ten to fourteen days. As temperatures cool in the fall, a second surge of growth occurs for cool-season grasses, requiring a return to a more frequent schedule to prepare the turf for winter. The mowing season concludes with a final cut in the late fall, performed just before the first hard frost, which helps protect the turf crown from matting and disease during the dormant winter months.