Spring represents a period of intense growth for turfgrass, making it a critical time for establishing a healthy lawn that can withstand the stresses of summer. The timing and frequency of cuts during this season have a direct effect on the grass’s long-term health and resilience. Getting your spring mowing routine right helps your lawn transition smoothly out of winter dormancy, encourages deeper root development, and naturally suppresses weeds.
When to Begin the Spring Mowing Cycle
The timing of your first spring mow should be determined by environmental cues rather than a fixed calendar date. You should wait until the grass has actively emerged from winter dormancy and exhibits consistent vertical growth. This usually correlates with soil temperatures reaching between 45°F and 55°F for cool-season grasses like fescue and bluegrass, or 60°F to 65°F for warm-season varieties such as Bermuda and Zoysia.
The physical condition of the turf and the soil beneath it are equally important signals. Before starting the mower, ensure the soil is dry enough to support the weight of the equipment and foot traffic without becoming compacted. Mowing on soggy ground can cause ruts and squeeze the air out of the soil, which damages the grass roots and restricts growth.
A good rule of thumb is to wait until the grass blades have reached a height of about 3 to 4.5 inches before the first cut. Before this initial cut, clean up any accumulated winter debris, such as fallen branches or matted leaves, to prevent damage to the mower and the turf. Delaying the first mow until the proper height is reached ensures the grass has enough leaf surface area to generate the energy needed for robust spring growth.
The Golden Rule for Mowing Frequency
The frequency of mowing in spring is dictated by the rate of grass growth, not a weekly schedule, and is managed by adhering to the “one-third rule.” This principle states that you should never remove more than one-third of the grass blade’s height in a single mowing session. This rule is crucial because it minimizes stress on the grass plant and maintains the necessary leaf surface for photosynthesis, the process that creates food for the plant.
Removing too much of the blade at once, often called scalping, can temporarily halt root growth, which weakens the plant’s overall health and ability to withstand heat or drought later in the season. By only taking a small portion of the blade, you preserve the plant’s energy reserves and encourage it to grow laterally, leading to a denser, healthier turf that naturally crowds out weeds.
To apply this rule practically, you must calculate the maximum height your grass should reach before you mow. For instance, if your desired finished height for the lawn is 3 inches, you should mow when the grass reaches 4.5 inches (removing 1.5 inches, which is one-third of the total height). If you maintain a finished height of 4 inches, you must mow when the grass reaches approximately 6 inches.
Because spring growth can be rapid, especially after rain, this rule may require you to mow more frequently than once a week during peak periods. Consistent adherence to the one-third rule, even if it means mowing twice in a week, ensures that the grass is never severely stressed and can maintain its healthy root-to-shoot balance. If the grass does get too tall, it is better to gradually reduce the height over two or three separate mowings rather than cutting it all down at once.
Setting the Ideal Blade Height for Spring
Choosing the correct cutting height for your mower is a significant factor in promoting a healthy spring lawn, as taller grass offers several biological advantages. A higher cut allows the grass blades to shade the soil, which helps to maintain a cooler root zone and reduces water evaporation. This shading also acts as a natural weed control, as it prevents sunlight from reaching weed seeds and inhibiting their germination.
In general, most turf experts recommend maintaining a high setting during the active spring growth period. For common cool-season grasses like Kentucky Bluegrass, Fescue, and Perennial Ryegrass, an ideal finished height is typically between 3 and 4 inches. This height maximizes the leaf surface area for photosynthesis, supporting the development of a deep and robust root system.
Warm-season grasses, such as Bermuda, Zoysia, and St. Augustine, tolerate and prefer a slightly lower cut, with recommended spring heights usually falling between 2 and 2.5 inches. While you may choose a slightly lower height for the very first cut of the season to remove old, dead winter growth, the height should be raised for all subsequent spring mows.
Blade Sharpness
Keeping the blades sharp is also important, as dull blades tear the grass, leaving ragged edges that make the turf susceptible to disease and stress.