When laying grass seed for a new lawn, many people apply a straw blanket or similar erosion control matting. This temporary cover creates a beneficial microclimate for the seeds and soil. Homeowners often wonder if this material should be removed once the grass begins to grow. The answer depends entirely on the specific materials used in the blanket’s construction, which determines if it will naturally break down or must be physically taken away.
The Purpose of Erosion Control Blankets
Erosion control blankets are installed immediately after seeding to create a controlled environment for germination. They function primarily by stabilizing the soil surface against external forces like wind and heavy rain, which can displace seeds and topsoil. This physical barrier prevents washouts and keeps the seed-to-soil contact intact, which is necessary for root establishment.
The straw or fiber component acts as a mulch layer, shading the soil and significantly reducing moisture evaporation. This moisture retention is beneficial during the germination phase, as grass seeds require consistent dampness to sprout. The matting also helps moderate soil temperature, preventing fluctuations that can stress new seedlings. The blanket serves as a temporary protective shell until the young grass develops a strong enough root system to survive independently.
Defining Biodegradable and Synthetic Materials
The decision to remove a blanket depends entirely on the composition of the materials used, particularly the netting holding the fibers together. Erosion control blankets are categorized into two main types: those made entirely of natural materials and those that incorporate plastic components.
Fully biodegradable blankets use natural fibers for the matting, such as straw, coconut coir, or excelsior (curled wood fiber). These are bound by fine threads made of materials such as jute or cotton. These mats are engineered to decompose completely over a period of months to a few years, adding organic matter back into the soil as they break down.
In contrast, many blankets use natural fibers but are held together by synthetic netting, often polypropylene or other plastics. This plastic netting is frequently green or black. While sometimes marketed as photodegradable, it does not truly decompose into the soil. Photodegradable plastic only breaks down into smaller pieces under ultraviolet light, contributing to microplastic pollution. Identifying the netting material—checking for plastic threads that do not easily tear—is the first practical step for a homeowner.
When and How to Remove Non-Biodegradable Netting
If a blanket contains synthetic netting, removal is necessary to prevent long-term damage and hazards. Leaving the plastic in place can strangle expanding grass roots, creating dead patches. The netting also risks entanglement with lawnmower blades, which can damage equipment or shred the plastic.
The optimal time for removal is after the new grass reaches two to three inches high and has been successfully mowed at least once or twice. This timing, usually six to eight weeks after seeding, ensures the grass has established deep enough roots.
To remove the netting, first cut the plastic mesh into manageable sections using a utility knife or scissors. Gently roll up the pieces, pulling slowly and parallel to the ground to minimize disturbance to the turf. If resistance is felt, indicating strong rooting through the mesh, the remaining netting should be cut away carefully at the soil line to avoid pulling out young seedlings.
Managing the Breakdown of Biodegradable Blankets
For blankets composed of natural fibers and netting, manual removal is neither required nor recommended. These materials remain in place, continuing erosion control until the grass is fully established. The straw and natural netting gradually weaken and break down through exposure to moisture, sunlight, and soil microorganisms. This process typically takes between three months and two years, depending on the material blend and climate.
As the blanket decomposes, the organic matter is incorporated into the topsoil. This acts as a mild, slow-release amendment that improves soil structure and water retention. The new grass grows directly through the thinning mat, which eventually integrates seamlessly with the lawn surface. Homeowners should resist pulling up sections, as this can damage developing root systems. As the matting thins, monitoring moisture levels becomes important, as the protective mulch layer will be less effective at preventing evaporation.