The anatomy of artificial turf, layer by layer

The part everyone means when they say "the grass" is the fiber: strands of polyethylene or nylon, tufted or woven into rows, cut and textured to look and feel like blades of natural grass. Fiber shape, thickness, and the way it is textured determine how soft the turf feels underfoot and how well it stands back up after being walked on, sat on, or brushed against by a mower along the border. Fiber is also the layer most exposed to the sun, since it sits on top of everything else, which is why it is the layer that fades and gradually stiffens over years of UV exposure. A fiber that looks slightly duller or feels a bit stiffer than it did when new is simply weathering the way any outdoor plastic does; it is not a sign anything underneath has failed.

Woven into the base of the fibers, often in a slightly different, lighter shade of green or brown, thatch is what gives turf body and a more natural, layered look rather than the flat, uniform rows a fiber-only surface would show. It also helps the fibers stand upright by giving them something to lean against between the grains of infill. Thatch does not need any separate care of its own; it is simply part of what a power brush lifts and fluffs along with the fibers on top of it, and part of why brushed turf looks fuller than turf that has only been rinsed.

Underneath the fibers and thatch is the backing, the material the fibers are actually stitched or tufted into, and the layer that gives the whole system its structural strength. Backing is built with drainage holes perforated through it so water can pass down and through rather than sitting on top of the turf. It is also where a surprising amount of the odor problem in pet turf actually lives: urine and other residue that gets past the infill settles directly on the backing, in the seams and stitching, which is exactly why a surface rinse alone so rarely solves a persistent smell. Reaching the backing, not just the fibers, is the part of a proper clean a garden hose cannot do on its own.

Sand or a similar granular material poured down into the fibers to weigh them down, hold them upright, and give the surface some cushion underfoot. Infill does the most day-to-day work of any layer in the system and is also the layer most often topped up or replaced outright, since it is what compacts under years of traffic, saturates with residue in a pet zone, or gradually washes thin from rain and rinsing. Depth matters as much as the infill itself: too little and fibers lie flat with nothing supporting them; too much and it buries the fiber tips. Our infill explainer covers this layer in more depth on its own.

Below the backing sits a compacted aggregate base, built with slope and drainage in mind so that water passing through the turf above continues down and away rather than collecting underneath it. A properly built base is what keeps turf from feeling spongy, developing a low spot, or holding a puddle years after installation, and it stays completely out of sight for the life of the turf if it was built correctly. It is also, by a wide margin, the most difficult and expensive layer to fix after the fact, since correcting it means lifting the turf that sits on top of it.

Around the perimeter, a strip of edge restraint, often metal or rigid plastic staked into the ground, holds the turf and the base material in place so that mowing edges, foot traffic and years of rain do not gradually work the border loose. Edge restraint that has failed or was never properly secured is usually what is behind turf that has started to lift, gap or curl at a border, and it is also the entry point that lets weeds and soil work their way in from outside the system, a different cause than the airborne seeds that root in dirty infill mid-lawn.