For stone tracks, drives and estate roads that have gone to potholes, ruts and a grass strip down the middle. Grading reshapes the surface you already have, pulling loose material back into the holes and restoring a camber so rain runs off instead of sitting in the track.
A grading blade, on a tractor or a purpose-built grader, cuts the surface down to the bottom of the potholes and drags the stone back across the track, then reshapes it with a crown or cross-fall so water sheds to the sides. The track is often rolled afterwards to firm it up.
Grading works with the material already in the track. Where the surface is worn thin, extra stone such as scalpings or crushed hardcore may be brought in and graded in with it.
Drainage is half the job. Clearing the edges, reopening side ditches and cutting or clearing the cross drains keeps water off the surface, and it is standing water that makes potholes in the first place.
Grade when the track is damp but not wet. Bone-dry stone will not bind and turns to dust, while saturated material smears and slumps. Spring and autumn usually give the best conditions.
Many tracks benefit from grading once or twice a year, before potholes get deep. Leaving it until the track is badly broken up often means it needs rebuilding rather than grading.