Infill sand serves several purposes. It covers the backing of the artificial grass between the blades, which both protects the backing from excessive UV exposure for longevity, as well as keeping it cooler. Infill sand is also needed to keep the blades of the turf standing upright, and returning to it’s upright position when walked on. Artificial grass blades are directional and lay flat when it comes off the roll. Brushing up the grass and applying a layer of infill sand supports the blades at the base where it bends at the base of the stitch.