FieldTurf and similar synthetic turf systems are made of plastic grass blades, a granular infill that sits between the blades, a woven backing that holds everything together, and a foundation of crushed stone underneath. Each layer uses different materials, and the choices affect how the field feels, performs, and holds up over time.
The Grass Blades: Plastic Fibers
The green blades you see and touch are thin ribbons of extruded plastic, typically polyethylene or polypropylene. Polyethylene is the more common choice for athletic fields and high-traffic installations because it’s softer, more resilient, and closely mimics the look and feel of natural grass. It holds up well under heavy use and is usually treated to resist fading from UV exposure.
Polypropylene is lighter and cheaper but less durable. It tends to show wear faster, so it’s more often found in decorative landscaping or low-traffic residential settings. Some turf products blend both fiber types or add nylon for extra stiffness in certain applications. The fibers are tufted into a backing fabric in rows, much like carpet, and cut to varying heights depending on the sport or use.
Infill: What Sits Between the Blades
Infill is the loose material packed between the turf fibers. It’s the layer you feel compressing underfoot, and it serves three purposes: weighing the turf down, cushioning impacts, and keeping the blades standing upright. The most widely used infill on sports fields is crumb rubber, made from ground-up recycled car and truck tires. Two forms exist, ambient and cryogenic, referring to how the tires are processed. The rubber granules can be coated with colorants or antimicrobial substances.
Silica sand is another common infill, sometimes used alone and sometimes mixed with crumb rubber. High-purity silica sand (above 90% purity) resists crushing and bacterial absorption. It’s far cheaper than alternatives. Filling a standard 90,000-square-foot field with silica sand costs roughly $15,000, while coated sand systems can run around $280,000 for the same area. Coated sand products seal high-purity quartz or silica grains with an acrylic or elastomeric layer, blocking bacteria from penetrating the grain surface.
Natural infill alternatives are also available. Some fields use a mix of cork and coconut husks blended with sand, typically about 10 to 15 percent organic material and 85 to 90 percent sand. These organic infills avoid the odor associated with crumb rubber and are easier to recycle, but they can compact and harden without proper maintenance, which affects both performance and safety.
The Backing: Holding It All Together
Turf backing is the fabric layer that the fibers are stitched into. Most systems use a two-part design. The primary backing is a woven or non-woven fabric that provides the structure for tufting. The secondary backing is a coating applied to the underside to lock the fibers in place and add strength.
Latex backing uses a water-based adhesive that solidifies as it dries, providing flexibility. Polyurethane backing is more rigid and durable. Many high-end fields use a dual backing system: a latex layer first for flexibility, then a polyurethane layer on top for strength and dimensional stability. This combination resists stretching and warping in extreme weather and heavy use.
Shock Pads: The Cushion Layer
Beneath the turf carpet, many athletic fields include a separate shock pad to absorb impact and protect against head and joint injuries. These pads come in several forms. Some are made from foamed polyurethane supplied in long continuous rolls. Others use small beads of polypropylene molded under pressure into a structured design. Closed-cell foam pads may use cross-linked polyethylene or PVC nitrile rubber, extruded for uniform thickness. Some pads mix small stones, foam, and rubber granules bound together with a polyurethane binder. A few even incorporate recycled athletic shoe materials.
The Foundation Underneath
Before any turf is laid, the ground itself needs preparation. A proper sub-base typically consists of class II road base (a blend of recycled concrete or asphalt in a sand-gravel mixture with particles up to three-quarters of an inch) or decomposed granite. This layer is compacted and graded to create drainage, since synthetic turf can’t absorb water the way soil and natural grass roots do. Perforated drainage pipes may run beneath or within the stone layer to channel rainwater away from the surface.
Heat Retention on Synthetic Surfaces
The plastic and rubber materials in synthetic turf absorb and hold heat far more than natural grass. Research from the University of Kansas found that surface temperatures on artificial turf averaged about 95°F compared to 75°F on natural grass under the same conditions. On the hottest days, turf surfaces reached as high as 136°F, while grass fields topped out around 91°F. This temperature difference is driven by the dark-colored crumb rubber infill and the plastic fibers themselves, which lack the evaporative cooling that living grass provides.
Chemical Concerns in Turf Materials
Synthetic turf components contain chemicals that have drawn increasing scrutiny. PFAS, a group of persistent synthetic chemicals sometimes called “forever chemicals,” have been detected across all three turf components: blades, infill, and backing. A 2022 study by Stockholm University researchers found total fluorine in 100% of turf samples tested, with concentrations ranging from 12 to 661 parts per million depending on the component. PFAS can enter turf through manufacturing processes, where fluoropolymers are used as processing aids during plastic extrusion, and through recycled materials that may carry older, long-chain PFAS compounds into newer products.
Lead content is another regulated concern. The industry standard ASTM F2765 sets specifications for total lead content in synthetic turf fibers, measured in milligrams per kilogram. Manufacturers seeking safety certifications must demonstrate their products fall below established thresholds, and regulatory authorities use these standards to verify claims.
Microplastic Loss Over Time
Synthetic turf fields gradually shed their materials into the surrounding environment. A study analyzing Norwegian turf fields found that each field loses an average of 900 kilograms (roughly 2,000 pounds) of crumb rubber granules per year. Across all fields studied, this totaled 1,187 tons of rubber particles annually, and the rate increases over time as fields age and undergo regular maintenance like brushing and grooming. These granules wash into storm drains, nearby soil, and waterways, contributing to microplastic pollution. This loss is one reason some municipalities have begun requiring containment barriers around turf fields or switching to alternative infill materials.