Top dressing a lawn means adding organic material, river sand, to the surface of the turf. The purpose of top dressing is to fill in minor low areas that have developed over the seasons, and to build up an ideal soil layer over the years. Top dressing also enables the turf to grow thicker which helps prevent weeds. The soil surface is gradually built up which helps thatch decompose in this layer and drought resistance is improved. Top dressing will increase nutrition uptake of the lawn, balance moisture content of soil, alleviate compaction and enhance root development.