Artificial grass infill is a granular material spread across the synthetic turf after installation, settling down between the individual grass blades. It is an integrated component of the artificial turf system that ensures the lawn functions correctly and maintains its appearance over time. Without the proper infill, the synthetic fibers would quickly flatten, and the turf itself would be susceptible to movement and wrinkling. Choosing the right infill material impacts the longevity, safety, and performance of the finished lawn.
The Primary Requirement: Why Infill is Essential
The inclusion of infill serves several distinct, mechanical purposes that contribute to the turf’s overall integrity. A primary function is providing ballast, which is the necessary weight to anchor the turf backing and prevent the entire sheet from shifting, buckling, or developing wrinkles due to thermal expansion and contraction. This added mass, often applied at a rate of one to two pounds per square foot, keeps the turf securely in place against wind lift and heavy foot traffic.
Infill also acts as a crucial support structure for the synthetic blades, keeping them standing upright. When the grass fibers are supported, they are less prone to matting or fraying, which prolongs the aesthetic life of the turf. The material cushions the base of the fibers, absorbing the impact from footsteps and protecting the primary backing from UV radiation. Furthermore, the granular composition of the infill ensures efficient drainage by allowing water to filter quickly through the turf system and into the prepared sub-base below.
Standard Sand Options: Silica and Washed Sand
The most common and cost-effective infill material is silica sand, derived from natural quartz. It is chosen for its hardness and durability, providing reliable weight and support for the turf fibers. For residential and landscape applications, silica sand must be specifically processed: washed to remove organic contaminants and kiln-dried to ensure it flows freely.
Unwashed sand contains fine dust and impurities that can hinder drainage and encourage the growth of mold or weeds within the turf system. The kiln-drying process removes all moisture, preventing the sand from clumping and ensuring even distribution during installation. Particle size is important; medium grades, such as 16/30 mesh, are standard for most lawns, balancing effective drainage with blade support. A rounded or sub-rounded grain structure is preferred because it resists compaction and minimizes abrasive wear on the synthetic fibers.
Specialized Infill Materials and Enhancements
Beyond standard silica sand, specialized infills exist to address specific performance needs. For pet owners, Zeolite infill is a popular option; this natural mineral, formed from volcanic ash, possesses a porous structure that absorbs ammonia molecules from pet urine. This trapping action effectively neutralizes odors, requiring periodic rinsing to flush the material. Because Zeolite is relatively lightweight, it is often applied as a top layer over a heavier base infill like sand to ensure the turf remains properly anchored.
Another enhanced option is acrylic-coated sand, which encapsulates standard sand particles in a durable polymer coating. These products often incorporate antimicrobial additives, which inhibit the growth of bacteria, mold, and mildew, making them suitable for play areas or pet turf. The coating also gives the sand a rounded, uniform shape, which reduces compaction and abrasion on the turf blades. Specialized cooling infills, such as HydroChill, are also available; these products store moisture and use evaporative cooling to reduce the surface temperature of the turf by as much as 30 to 50 degrees Fahrenheit compared to traditional sand when hydrated.
Installation and Maintenance Considerations
The application of infill is a multistep process that must be executed carefully to ensure even distribution and optimal turf performance. After the turf is laid and secured, the fibers must be brushed or “groomed” upward using a stiff brush or a power broom to create a vertical pile. This action opens the turf, allowing the infill material to penetrate down to the backing layer.
The infill should be applied using a drop spreader to ensure a consistent and uniform layer across the surface. It is recommended to spread the total required amount in several light passes, rather than one thick layer, brushing the infill between each pass to work the granules down into the base of the turf. This layering technique prevents the infill from sitting on top of the blades and promotes proper settling. Over time, foot traffic and environmental factors can cause the infill to compact or migrate, so periodic grooming with a power broom and a light top-up of material may be necessary to maintain blade support and resiliency.