Soil Compaction

After prolonged rainfall, soil can become waterlogged. If it is then walked on or driven over, the soil can become compacted, which impedes drainage and makes it harder for air, water and fertiliser to penetrate into the roots.

Compaction is the reduction of soil pore space. Soils are generally 50% pore space and 50% solid. The pore space is needed to conduct water and oxygen to your lawn turf and many thousands of other plants, microbes and animals that live in the soil. When the pore space is reduced by even 10%, your lawn turf will suffer.

The lawn turf will grow slowly and it will be short. Eventually it will become thin, allowing weeds, algae or moss to grow.

The compaction generally occurs within a few millimetres under the turf. If heavy equipment is used the compaction can reach a depth of 300mm or more. For example, the repeated parking of cars on lawn turf will compact the soil. Lawn turf soils that are compressed when wet, compact deeper and faster than dry soils. Clay soils compact more than sandy soils.


Healthy lawn turf will cushion the soil from occasional activities such as running, mowing the lawn and animal traffic, but any repeated activity will eventually cause compaction.

If your lawn turf is not growing well and water is collecting on the surface you may have a problem with compaction.

To prevent and relieve soil compaction you must aerate your lawn. Click here for more details.