The first mowing of the season is a foundational moment for the health and appearance of your lawn. It signals to the turfgrass that the growing season has begun, encouraging a strong, healthy recovery from winter dormancy. Properly executing this initial cut removes dead, matted grass tips, allowing sunlight and air to reach the new growth beneath. This process sets the desired growth pattern, promoting dense, uniform turf instead of tall, spindly blades. A well-timed first mow influences the grass’s ability to photosynthesize and develop deep, resilient roots.
Determining the Ideal Seasonal Timing
The correct time to perform the first mow is determined by biological signals from the grass itself, rather than by a specific date on the calendar. Grass must be actively growing to withstand the stress of cutting, which happens when soil temperatures consistently reach a certain threshold. For cool-season grasses like Kentucky bluegrass and fescue, active growth begins once the soil temperature is sustained around 45°F to 55°F. Warm-season grasses, such as Bermuda and Zoysia, require a warmer soil temperature, often closer to 65°F, before they emerge from dormancy.
Waiting until the grass is actively growing ensures the plant has the energy reserves to recover from the cut and minimizes the risk of damage. Mowing too early can shock the fragile new shoots, while waiting too long allows the grass to become overgrown, which can lead to matting and disease. A good visual indicator is grass height; the turf should reach approximately four to five inches before you consider mowing for the first time.
Essential Pre-Mowing Preparations
Before the mower is even started, several practical steps must be completed to ensure a safe, effective, and healthy first cut.
Clearing Debris
The first action is to thoroughly clear the lawn of any debris accumulated over the winter, such as fallen branches, leaves, or rocks. These items can damage the mower blade or be hurled out, creating a safety hazard. Raking the turf also helps remove matted, dead grass and allows air and sunlight to penetrate new growth underneath.
Checking Soil Moisture
The condition of the soil is an important factor, as mowing when the ground is too wet is detrimental. Operating a heavy mower on saturated soil causes severe compaction, which limits the flow of oxygen and water to the grass roots. To test the moisture level, perform a simple “squish test”: if your shoes leave visible, soft indentations, the soil is too wet, and you should wait a day or two. Mowing wet grass also results in an uneven cut and causes clippings to clump together, which can smother the turf.
Sharpening the Blade
Preparing the equipment is a fundamental step, particularly checking the sharpness of the mower blade. A dull blade tears the grass blades instead of making a clean cut, which stresses the plant and leaves jagged, brown tips susceptible to disease. Sharpening the blade ensures a precise severance, allowing the plant to heal quickly and dedicate its energy to healthy growth.
Setting the Deck: The First Cut Technique
The mechanical execution of the first mow requires specific adjustments to the mower deck to avoid stressing the newly emerging turf. The primary rule governing this cut is the “one-third rule,” which dictates that you should never remove more than one-third of the total grass blade height in a single pass. This practice ensures that enough leaf surface remains for the grass to efficiently photosynthesize and produce the energy needed for recovery and root development.
For the first cut, the mower deck should be set to its highest functional setting, or at least higher than your typical summer cutting height. If your lawn has grown to six inches over the winter, the first cut should only reduce the height to about four inches, leaving two-thirds of the blade intact. This higher setting is important in the spring because it protects the grass’s crown, the growth point at the base of the plant, from being accidentally scalped.
Moving the mower at a slightly slower pace than normal is also advisable for the initial cut, as this allows the blades to create an even, clean pass. If the grass is significantly overgrown, it may be necessary to wait a few days after the first cut and then perform a second, slightly lower cut to gradually reach the desired height. This staged approach is gentler on the grass than attempting to cut it back all at once, which can lead to browning and prolonged shock.