Aeration is a lawn maintenance practice designed to encourage healthier turf. The process involves mechanically perforating the soil with small holes, typically by removing plugs of soil and thatch (core aeration). This action relieves soil compaction, which restricts the circulation of air, water, and nutrients within the root zone. Preparation is necessary to maximize the benefits of this procedure and ensure the aerator achieves the desired depth of penetration.
The Necessity of Mowing Before Aeration
Mowing the lawn before aeration is necessary, as it directly impacts the efficiency and success of the process. Long grass blades can interfere with the aerating machine, potentially tangling around the tines or reducing the depth of soil penetration. A shorter turf allows the aerator’s tines to cleanly punch through the grass and thatch layer, making solid contact with the soil surface.
Shorter grass also assists in the post-aeration stage. Core aeration machines extract cylindrical plugs of soil and thatch, which are deposited directly onto the lawn surface. These plugs contain beneficial microorganisms that help break down the thatch layer as they decompose over the following weeks.
If the grass is too long, the expelled soil cores can become trapped within the dense turf canopy, hindering their ability to break down quickly. A shorter lawn ensures the cores land on the grass and are exposed to the elements, allowing them to crumble and release nutrients back into the soil more rapidly. If overseeding is planned immediately after aeration, a short cut ensures the new grass seed makes direct contact with the newly exposed soil, which is necessary for germination.
Determining the Ideal Cutting Height
To achieve effectiveness, the grass should be cut significantly shorter than its typical maintenance height immediately before aeration. Most experts suggest a final cutting height in the range of 1.5 to 2 inches, though this varies depending on the specific grass type. This reduced height provides a clear path for the aerator tines to penetrate the soil without resistance from the leaf blades.
It is important to avoid “scalping,” which removes more than one-third of the grass blade in a single session and can severely stress the turf. If the grass is currently tall, the height should be lowered gradually over a series of days leading up to the aeration date to safely reach the 1.5 to 2-inch target. This incremental reduction minimizes shock to the grass plant, ensuring the lawn remains healthy enough to recover quickly from the aeration process.
Other Critical Preparations Before Aeration
Beyond mowing, two other preparatory steps are necessary for successful core aeration: proper soil hydration and marking subterranean obstacles. The effectiveness of a core aerator depends on the soil moisture content. Soil that is too dry will be hard and prevent the tines from penetrating to the depth of 2 to 3 inches. Conversely, overly saturated, muddy soil can clog the machine or make the plugs difficult to extract cleanly.
A deep watering of the lawn, providing about one inch of water one to two days before aeration, is recommended to achieve the ideal moist, but not soggy, soil condition. This allows the aerator tines to cut cleanly and pull out long soil cores. A simple test for readiness is pushing a screwdriver into the ground; it should penetrate the soil easily.
The final preparation involves marking any obstacles that lie beneath the turf. Core aerators are heavy machines with deep-reaching tines, and they can easily damage shallow irrigation lines, sprinkler heads, or invisible dog fences. Using wire flags to mark the location of all known hazards is necessary to prevent damage to the property and the rental equipment.