The use of straw is a widely accepted practice when establishing a new lawn from seed, serving as a temporary, protective mulch. This light layer helps regulate soil temperature, preventing excessive heat that can dry out delicate seedlings. The straw also acts as a barrier, shielding seeds from wind and water erosion while retaining moisture necessary for successful germination. Now that the grass is established and has grown several inches high, a decision must be made on how to manage the residual material. The next steps depend on assessing the condition of the remaining straw layer on the new turf.
Assessment: To Remove or Not to Remove?
The decision to actively remove the remaining straw is based primarily on the density and thickness of the layer. If the straw was applied correctly, allowing approximately 50% of the soil to remain visible, it is thin enough to be left in place. A thin, loosely distributed layer will naturally break down without suffocating the new grass. Conversely, if the straw forms thick clumps or a heavy mat, it blocks sunlight and air, preventing photosynthesis and potentially leading to disease. Non-certified straw may also contain weed seeds that will sprout and compete with the turf. If the layer is heavy or if unwanted weeds are emerging, physical removal is the appropriate choice.
The Strategy for Gradual Breakdown
If the straw layer is light and evenly dispersed, the best approach is to allow it to decompose naturally into the soil. This process is accelerated by mowing the lawn when the new grass reaches 3 to 4 inches high. Set the mower deck to its highest setting and use a mulching function, allowing the clippings and straw fragments to be finely chopped. Chopping the straw into smaller pieces increases its surface area, speeding up decomposition.
Straw is a high-carbon material, often having a Carbon-to-Nitrogen (C:N) ratio ranging from 40:1 to 150:1, while microbes require about 30:1 for efficient breakdown. Consequently, microbes temporarily draw nitrogen from the surrounding soil to break down the carbon-rich straw, which can briefly deplete nutrients available to the grass roots. Applying a light, nitrogen-rich fertilizer three to four weeks after germination helps offset this process, ensuring the new lawn maintains its nutrient supply. With regular mowing and watering, the remaining straw should fully break down within a few weeks to a few months.
Methods for Physical Removal
For areas where the straw is too dense or clumpy, physical removal is necessary to prevent the grass from being smothered. Wait until the new grass seedlings are well-established, ideally after the first or second successful mowing. Young grass plants have shallow root systems that are easily disturbed, so removal must be executed gently. Use a light, plastic leaf rake rather than a heavy metal garden rake, which can easily tear out the new seedlings.
Work slowly using soft, upward strokes to gently lift the straw off the grass blades without making contact with the soil. This technique separates the straw from the turf while leaving the young root systems intact. Aggressive raking will damage the fragile grass and create bare patches that require reseeding. After collecting the excess material, the new lawn should be immediately watered to help settle any disturbed soil and reduce stress on the newly exposed grass.
Repurposing or Disposal Options
Once the straw has been carefully removed from the lawn, it can be repurposed effectively in other areas of the landscape.
- It is an excellent “brown” material for a home composting system due to its high carbon content. Mix it with “green” materials like grass clippings or vegetable scraps to balance the C:N ratio for rapid decomposition.
- The removed straw can be used as a beneficial mulch layer in vegetable gardens.
- It helps suppress weeds and retain moisture for established plants.
- If the straw was part of an erosion control blanket that included synthetic netting, it must be disposed of as general refuse, as the non-biodegradable mesh cannot be processed by standard composting facilities.