Laying new sod offers an immediate, lush lawn, but the work continues with the first mowing. This initial cut is a delicate but highly important task that directly influences the long-term success of the lawn. Executing this cut correctly is fundamental for encouraging the fragile new root system to anchor deeply into the soil. Proper technique and timing prevent damage to the new grass blades and ensure the sod fully establishes itself.
Determining When to Mow
The decision to mow for the first time is based on root development, not a fixed date on the calendar. While many lawns are ready approximately 10 to 21 days after installation, this timeframe varies depending on weather, grass species, and watering frequency. The grass should be visibly taller, typically reaching a height of about three to four inches, before the first cut.
The definitive test for readiness is the “tug test,” which assesses how well the roots have knit into the native soil. Gently lift a small section of the sod near an edge or seam. If the sod resists your pull and feels firmly anchored, it indicates that the new white roots have begun to establish a grip.
If the sod lifts easily, it is not yet prepared for the stress of a mower and requires more time for root development. Mowing too early can dislodge the sections or damage the vulnerable young roots, setting back the establishment process. Waiting until the roots are firm minimizes the risk of tearing or lifting the turf when the mower passes over it.
Preparing the Mower and Sod
Preparation is important, beginning with the equipment. The mower blade must be sharpened to a razor edge to ensure a clean cut across the grass blades. A dull blade tears the grass, leaving ragged edges that stress the plant and make it susceptible to disease and pest infestation.
Setting the proper cutting height is paramount for this first session. The blade should be set to the highest possible setting on the mower deck, generally resulting in a cut height of three to four inches. This high setting ensures adherence to the “one-third rule,” a horticultural principle stating that you should never remove more than one-third of the grass blade’s total height in a single mowing.
For instance, if the grass has grown to four inches, the highest setting ensures you cut no more than about 1.3 inches off the top. This practice leaves sufficient leaf surface area for the plant to continue photosynthesis without inducing shock. Finally, the sod should be slightly dry before mowing; reduce watering the day before so the soil firms up and can support the mower’s weight without creating ruts.
The Proper Mowing Technique
Once the sod is dry and the mower is prepared, the technique requires careful maneuvering to prevent damage. The optimal path for the first cut is to mow perpendicular or diagonal to the direction the sod pieces were laid. This cross-cutting motion helps to avoid pulling up or separating the seams between the strips.
Movement across the new lawn should be slow and deliberate, especially when pushing a heavier walk-behind or riding mower. The equipment’s weight can compress the soil, so minimizing time spent in any one area helps avoid compaction. When turning, avoid tight pivots on the new turf; instead, lift the mower deck or guide the machine onto a paved area or established border.
The decision to bag or mulch clippings depends on the volume of removed material. If the grass was allowed to grow tall and the clippings are heavy, bag them to prevent thick clumps from smothering the new grass. If the cut is light and follows the one-third rule, the fine clippings can be mulched and left on the lawn to return organic matter and nutrients to the soil.
Establishing a Regular Cutting Schedule
After the successful first mow, establish a consistent cutting routine that continues to promote deep root growth. Continue to follow the one-third rule, which means you may need to mow more frequently than a fully established lawn, sometimes every five to seven days during rapid growth. This higher frequency ensures you are only trimming the top portion of the blade each time.
Maintain the high cut setting for the first several weeks to keep the grass blades long, encouraging a deeper, more resilient root system. Shorter grass forces the plant to divert energy from root growth to leaf regeneration, which is counterproductive during establishment. You can begin gradually lowering the height of the cut, if desired, only once the sod is completely anchored and showing vigorous growth.
Following the first mow, reintroduce water to the lawn to help the grass recover from the stress of being cut. A light but thorough watering immediately after mowing helps settle the remaining turf and rehydrate the exposed grass blades. Maintaining this attentive watering and mowing schedule transitions the new sod into a robust, self-sustaining lawn.