How deep should mulch or gravel be?
| Use | Recommended depth |
|---|---|
| Mulch in flower beds | 2–3 in (5–7.5 cm) |
| Mulch around trees | 3–4 in (7.5–10 cm) |
| Gravel path | 2–3 in (5–7.5 cm) |
| Gravel driveway | 4–6 in (10–15 cm) |
| Topsoil for new lawn | 4–6 in (10–15 cm) |
| Sand base for pavers | 1 in (2.5 cm) |
How is it calculated?
Volume is length × width × depth. In imperial, depth in inches is divided by 12 to get feet, and cubic feet are divided by 27 to get cubic yards – the unit most landscape suppliers sell by. Weight uses typical densities: mulch ≈ 0.4 t/m³, topsoil ≈ 1.3 t/m³, sand ≈ 1.5 t/m³ and gravel ≈ 1.6 t/m³.
How many bags of mulch in a yard?
One cubic yard is 27 cubic feet, so it equals about 13.5 bags of 2 ft³ mulch or 9 bags of 3 ft³ mulch. Buying in bulk usually becomes cheaper than bags at around 2–3 cubic yards.
How much area does a yard of mulch cover?
At 3 inches deep, one cubic yard covers about 108 square feet. At 2 inches it covers about 162 square feet.