How deep should top dressing be?

Apply 5-10 mm at a time. For severely uneven lawns, repeat every 4-6 weeks during the growing season. Never bury the grass completely.

What is the best top dressing mix?

A standard mix is 70% sharp sand, 20% loam, and 10% peat-free compost. Match the mix to your soil type — sandy soils need more loam.

When should I top dress?

Top dress in autumn (September-October) or spring (April-May) when grass is actively growing. Avoid summer heat and winter dormancy.

Should I scarify before top dressing?

Yes. Scarify first to remove thatch, then overseed if needed, then apply top dressing. This is the ideal autumn lawn renovation sequence.

What is the best time to top dress a lawn?

September to October is ideal in the UK. The soil is warm, rain helps settle the dressing, and grass is actively growing to recover quickly.

GardenCalcs

Top Dressing Calculator — Lawn Levelling Mix

Calculate how much top dressing mix to level and improve your lawn.

Lawn Area

Measure the lawn's length × width in metres; subtract beds, paths and patios.

Application Depth

Light dressing 3-5 mm; up to 10 mm only when levelling — never bury the grass tips, brush it down between the blades.

Mix TypeStandard 70/20/10 suits most lawns; Sandy adds drainage on heavy clay; Rich adds organic matter for sandy, hungry soils.

Include 10% wastage

Adds a margin for uneven spreading and material lost when brushing in — leave on unless you are ordering loose by volume.

How We Calculate This

Volume = Area × Depth (converted to metres). Depth is usually expressed in mm for top dressing.

The mix ratios are: Standard (70% sand, 20% loam, 10% compost), Sandy (80/10/10), Rich (50/30/20).

Bag count assumes the standard UK 25 kg bag. A sand/loam top dressing has a bulk density of about 1.6 kg per litre, so each 25 kg bag holds roughly 15.6 litres — the calculator divides the required volume by this, not by 25.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.