Go 75 mm deep for mulch and 50 mm for compost dug into beds. Quick guide:
1 m³ covers about 13 m² of garden at 75 mm
2 m³ covers about 26 m², a typical front yard
4 m³ covers about 53 m², front and back beds
6 m³ covers about 80 m², a full makeover
Not sure? Use the coverage calculator below.