Artificial grass is actually comprised of multiple layers, each of which are made from various synthetic materials. The drainage layer is made of stone and geotextile, and is the bottom portion. There is sometimes a layer of padding or a leveling layer. The “grass” section is made from the same process as carpets are made: through the “tufting process.” A mix of synthetic materials (polyethylene, nylon, etc.) are mixed together, formed into imitation blades of grass via an extruder, and threaded into the backing material. To create a more accurate approximation of real grass, there’s usually a layer of crumb infill immediately beneath the backing.