Establishing a lawn – ground preparation, topsoil and sowing

1. Check the ground and drainage

Identify places where water collects and where it flows. Remove weeds, large stones and uneven plant debris from the area being established.

Deal with soft or unstable patches before adding the growing layer. New soil alone does not fix a weak or waterlogged base.

If fill is needed to raise the ground level, it belongs to the work beneath the rooting layer. Place and consolidate it according to the requirements of that fill and the site. Do not apply an aggregate-base compaction method automatically to the lawn’s growing medium.

2. Calculate the new growing layer

Choose soil or growing medium supplied for lawn establishment. Products sold as topsoil, compost and potting mix are not automatically interchangeable.

Assess how much existing soil is usable, then decide what must be added. The total rooting depth is not necessarily the depth of new material to buy.

Suppose the plan requires an additional 15 cm of growing medium over 100 m², with the depth measured in the finished layer:

100 m² × 0.15 m = 15 m³ = 15,000 litres.

Fifteen centimetres is an example assumption, not a GB/AU lawn-depth recommendation. Ask the supplier what delivered quantity will produce that finished layer and what settling assumptions are included.

3. Check that the surface is ready

Level the growing medium and remove large clods, stones and roots. Avoid working wet soil into a muddy or hard-compacted surface.

Before sowing, check that:

• the surface is at the intended level, without hollows that collect water;
• the ground does not give way underfoot and leave deep impressions;
• the upper surface has small crumbs that allow seed contact with the soil, rather than large clods separating the seed from it.

An even surface does not mean a horizontal one. Retain the planned fall for water movement.

4. Calculate and purchase the seed

Choose the mix for the intended use and local growing conditions. Use its rate for establishing a new lawn, not a separate repair or overseeding rate.

Lawn area × product sowing rate = seed required.

Fictional label example—not a recommended sowing rate: suppose a product specifies 25 g/m² and the lawn area is 100 m².

100 m² × 25 g/m² = 2,500 g = 2.5 kg.

If that product comes in 1 kg packs, buy 3 packs. They provide 3 kg, leaving a calculated 0.5 kg beyond the requirement. Do not sow the extra merely to empty the packs.

Use the actual label for your purchase. A shared English guide cannot prescribe one seed rate or sowing calendar for all GB and Australian locations.

5. Sow evenly and keep the seedbed moist

Distribute the calculated amount evenly. If the product recommends two crossing passes, divide the seed quantity into two portions.

Follow the mix’s instructions for covering the seed and pressing it lightly into contact with the soil. Do not assume one burial depth suits every seed mix.

Water after sowing without washing the seed away. Check the surface during germination and keep it moist, not flooded. Adjust watering to the weather and the rate at which the seedbed dries, rather than following a fixed daily timetable.

6. First mowing and normal use

Check the product’s care instructions for the growth height and cutting method for the first mow. Ask the supplier if that information is missing.

A green surface is not necessarily ready for normal use. The grass needs to be rooted and the ground firm enough to carry foot traffic. Delay normal use if walking leaves deep marks or dislodges seedlings.