As the name suggests, Turf Underlay is primarily used as a base soil for turf. It is made up of mainly soil with a touch of sand for drainage. Turf Underlay is also suitable for filling in holes but in its current form, there aren’t many nutrients in the mixture so it is not recommended for garden beds unless you are building it up and topping the garden bed with rich Garden Mix soil. This soil is not suitable for on top of your grass as it will smoother the blades and end up doing more damage than good. Strictly us it underneath the lawn for the best results.