Grass doesn't root very deeply, so you don't have to dig down far - you're not preparing a vegetable patch. Just ensure that the ground is not rock-hard beneath the lawn. Aim for a firm, but not compacted, even surface, with good drainage from the top inch or so, ensuring that the lawn won't be under water after heavy rain.

Digging in organic material is not a good idea because it continues to rot and shrink, making the ground above uneven. Uneven ground means the mower misses the dips and scalps the bumps, which isn't pretty.

• Dig the ground over when it is reasonably dry (if a lot of soil clings to your boots, it's too wet).
• After digging, rake the ground level, raking off larger stones as you go.
• Firm up the surfaceby treading the ground on your heels, shuffling up and down in one direction, raking the ground again, then treading again at right angles to the first direction, before raking level again. The treading produces a firm surface for the lawn; the raking provides a fine tilth for grass seed to germinate in and for turf roots to grow into.

Ground preparation for a lawn from seed or turf is the same, but for sown lawns it is essential to apply a pre-seed fertiliser at least a week before sowing, so it can be washed into the soil. If left on the surface, it could damage the new root emerging from the seed.

Delay sowing or turfing until a dry day with mild and wet weather forecast - usually March/April or August - but don't rely on the calendar alone - a wet summer is ideal for establishing a lawn.

There's no need to water after sowing because the seeds will take up moisture from the ground, but if there is a hot dry spell after turfing, you may need to water if the turves begin to shrink away from each other. However dry the weather, the turves should take root - you can check by gently peeling back the edge of a turf.