Soil forms the planting layer, while mulch and bark cover its surface; garden fertiliser supplies nutrients at a measured rate. Calculate the volume of soil required for a new garden bed before comparing bagged quantities with bulk volumes. Product descriptions should identify the intended use, since soil for an in-ground bed is not interchangeable with potting mix for a container.

Soil, Mulch and Fertilisers

Bark mulch also affects the finish of a planted area: particle size and colour change how the surface sits beside paving and edging. Leave room below adjoining paths for the specified mulch depth so loose material does not spill onto them. Gardens in Australia containing phosphorus-sensitive native plants need particular care when selecting garden fertiliser. Check the nutrient analysis and suitability statement rather than assuming a general-purpose formulation suits every plant.

How do I calculate the volume of soil needed?

Multiply the bed’s length by its width and intended fill depth, all in metres, to find the volume in cubic metres. Allow for any existing soil that will remain in the bed.

Where should mulch sit around new plants?

Spread mulch over the exposed soil, leaving a gap around stems and tree trunks. Keep the root flare visible rather than piling bark against the plant.

Can garden fertiliser be applied beneath mulch?

Read the label for placement instructions, as some fertilisers need contact with the soil rather than sitting on bark. Water it in only as directed, and avoid application before heavy rain.