For preparing a seedbed on stony, lumpy or rough ground – a new lawn, a reseeded paddock, a garden that has been built on, or a field corner full of rubble. A stone burier buries stones and clods below the surface and leaves a fine, level tilth ready to sow.
A stone burier looks like a rotavator, but its rotor spins in reverse. The blades throw soil up against a grid or screen at the back; fine soil passes through and falls on top, while stones, clods and turf are held back and fall to the bottom of the worked layer. The result is a bed of fine soil over the buried stones.
Most machines have a roller at the back that levels and firms the surface, and some carry a seeder on top, so the ground can be cultivated, levelled and sown in one pass.
Established turf usually needs spraying off, or a pass with a rotavator first, before the stone burier can work it down cleanly.
Stone burying needs dry, friable soil. Wet soil clogs the screen and gets smeared; the machine only works well once the ground has dried out enough to crumble.
For sowing grass, the usual windows are spring (roughly March to May) and late summer to early autumn, when the soil is warm and there is enough moisture for germination. Late summer sowings often establish better, with fewer weeds competing.