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Mulch depth guide
75–100 mm is the sweet spot for weed suppression and moisture retention. Less than 50 mm won't suppress weeds effectively.
Typical trailer capacities
6×4 trailer ≈ 0.7 m³ | 7×5 trailer ≈ 1.2 m³ | Ute tray ≈ 0.5 m³. Don't overfill — check your load limit.
Bags vs bulk
Bulk delivery is cheaper above 1 m³. Under 1 m³, bagged from a hardware store is often more convenient and similar in cost.
Order a little extra
Add 10–15% to account for settling, uneven ground, and edges. It's easier than a second trip to the yard.
Common questions
How do I calculate how much mulch I need?
Multiply your area in square metres by the depth in metres. A 20 m² garden bed at 75 mm depth needs 20 × 0.075 = 1.5 m³ of mulch. This calculator does that maths automatically across multiple areas and different shapes.
How many bags of mulch in a cubic metre?
One cubic metre equals 1,000 litres. A standard 30 L bag gives you about 33 bags per m³. A 40 L bag gives about 25 bags per m³.
How much does a cubic metre of mulch cost in Perth?
Bulk mulch from Perth landscape supply yards typically ranges from $45 to $90 per m³ depending on the type — pine bark, woodchip, or premium decorative mulches vary in price. Enter a price in the calculator above to get an estimate for your job.
How deep should mulch be?
75 mm is the Waterwise-recommended depth for Perth gardens — deep enough to retain moisture and suppress weeds without smothering plants. Top up annually as mulch breaks down.
How many trailer loads do I need?
A standard 6×4 trailer holds around 0.7 m³. A 7×5 holds about 1.2 m³. Select your trailer size in the calculator and the number of loads is calculated automatically.