The transition from winter dormancy to active growth is a delicate period for your lawn. The first cut of the season is crucial for the lawn’s health and vigor throughout the year. Mowing too early or incorrectly imposes significant stress on the emerging root system, which is recovering from the cold. Improperly timed mowing can also create entry points for disease and promote early-season weeds.
Environmental Triggers for the First Cut
The decision to start mowing should be based on biological cues. The grass must demonstrate active growth, typically reaching a height of 3.5 to 4 inches, before cutting. This visible growth indicates the plant has emerged from dormancy and begun photosynthesis, which is necessary to recover from the stress of being cut.
The start of growth is governed by soil temperature, as root development depends on consistent warmth. Cool-season grasses, such as Kentucky bluegrass and fescue, begin growing when the soil consistently reaches 50° to 55°F. Warm-season grasses like Bermuda or Zoysia remain dormant until soil temperatures stabilize around 65°F.
Waiting for this specific temperature threshold ensures the root system is robust enough to support the leaf blades after trimming. Cutting the lawn before the roots are fully engaged risks depleting the plant’s stored energy reserves, hindering its ability to thrive throughout the year.
Essential Lawn and Equipment Preparation
Before starting the mower, a thorough site and equipment check must be completed. Walk the entire lawn to clear away any winter debris, such as fallen branches, rocks, or matted leaves, which can damage the blade. Inspect the soil moisture using a simple “squish test.” If the soil feels spongy or water squishes up, the ground is too wet, and the cut must be postponed, as mowing wet grass results in uneven cuts, clumping, and compacts the soil.
Equipment readiness begins with a freshly sharpened mower blade. A dull blade tears and frays the tips, leaving jagged edges that turn white or brown, which leaves the plant susceptible to disease and pest infestation. A clean cut allows the grass to heal quickly, minimizing stress. Also, check the oil, spark plug, and fuel to ensure the engine runs efficiently for a uniform cut.
Execution: Setting the Proper Mowing Height
The technique for the first cut focuses on minimizing stress to the recovering turf, making the “one-third rule” mandatory. This rule dictates that you should never remove more than one-third of the total blade height in a single mowing session. For the first pass, set the mower deck to its highest recommended height, allowing for a light trim of only the tips of the blades.
Removing too much leaf tissue drastically reduces the surface area available for photosynthesis. This forces the grass to draw heavily on its root reserves, weakening the emerging root system and making it less resilient to heat and drought. A high initial cut ensures sufficient leaf blade remains to support energy production and deep root growth.
Handling Clippings
Mulching the grass clippings back into the lawn is generally beneficial, as the fine clippings return nitrogen and nutrients to the soil. However, if the grass is excessively long or matted from winter, the clippings should be bagged to prevent smothering the turf underneath. Heavy clumps of clippings block sunlight and trap moisture, creating conditions favorable for fungal growth and disease. If the grass is too tall to follow the one-third rule, cut it a second time after a few days, gradually reducing the height over multiple passes.