The Foundation of a Lasting Lawn
The health of your lawn is directly tied to the depth and quality of the soil beneath it. Turf will only grow roots as deep as the loose, nutrient-rich soil allows. If you lay turf over just 1 inch of topsoil sitting on hard clay, the roots have nowhere to go. In summer, that shallow 1-inch layer will dry out in hours, and the grass will die of thirst.
The Minimum Requirement: 4 to 6 Inches
For a robust, healthy, and drought-resistant lawn, you need an absolute minimum of 100mm to 150mm (4 to 6 inches) of loose, high-quality screened topsoil.
This depth provides a massive 'reservoir' for rainwater to drain into, preventing surface flooding. More importantly, it encourages the grass roots to drive deep into the earth. Deeply rooted grass can access moisture locked far below the surface, meaning your lawn will stay vibrantly green during a summer heatwave while your neighbors' shallow lawns turn yellow and die.