Topdressing with compost or sand

What it does

Topdressing is a thin layer of fine material brushed into the lawn surface. After overseeding it covers seed so it stays moist, fills aeration holes, and over repeated years levels small dips and improves the soil at the surface.

What to use

• Heavy clay soil: a sandy mix, such as 70% sand and 30% fine compost or loam, to improve drainage.
• Light sandy soil: more compost or loam, to hold water.
• Material must be fine, screened and dry enough to spread. Never use pure builder’s sand on clay; it can make drainage worse.

How much

Roughly 1–3 kg per m² (about 2–6 lb per 10 sq ft), which gives a layer of a few millimeters. The rule: you should still see the grass blades sticking out when you are done. Smothered grass yellows and dies.

How

Tip small heaps across the lawn, spread them with the back of a rake, then work the material into the surface with a stiff brush, a drag mat or a lute. Water lightly to settle it, then carry on with the watering schedule for the new seed.