How Much Mulch for a Garden Bed

Mulch for a Standard Garden Bed

The classic garden bed running along a fence or beside a house wall is one of the most common planting areas in Australian homes. A typical bed of this type measures around 4 metres long by 1.5 metres wide, giving you 6 square metres of garden space. At the recommended 75mm depth for general ornamental plantings, you'll need approximately 0.45 cubic metres of wood chip mulch to achieve proper coverage.

In weight terms, 0.45 cubic metres of wood chip mulch comes to around 180 kilograms. This is a manageable amount that falls into the decision zone between bagged and bulk purchases. Nine standard 20kg bags would cover your needs, though buying a half-cubic-metre bulk load often works out cheaper if you have multiple beds to mulch or want some spare for top-ups later in the season.

Preparing Your Garden Bed

Before spreading mulch, take time to prepare the bed properly. Remove any existing weeds, as mulch suppresses new weed growth but won't kill established plants. Water the soil thoroughly, particularly if conditions have been dry, since mulch will slow moisture evaporation once applied. If you're applying mulch around new plantings, ensure they're settled in and watered first.

Application Tips for Best Results

Spread mulch evenly across the bed, maintaining a consistent 75mm depth throughout. Around plant stems and shrub trunks, create a slight gap of a few centimetres to prevent moisture sitting against the plant and potentially causing rot. Along the fence or wall edge, keep mulch slightly back from the boundary to prevent moisture damage to timber or paint. Use a rake to level the surface for a neat finish that enhances your garden's appearance.

Need to calculate a different bed size? Our main mulch calculator handles any dimensions you have.