20 m² of beds at 7.5 cm deep take 1.50 m³ of mulch, or 30 bags of 50 L; 200 sq ft at 3 inches takes 1.85 cubic yards, or 25 bags of 2 cu ft.
| Area (m²) | 5 cm | 7.5 cm | 10 cm |
|---|---|---|---|
| 5 | 0.25 | 0.38 | 0.50 |
| 10 | 0.50 | 0.75 | 1.00 |
| 15 | 0.75 | 1.13 | 1.50 |
| 20 | 1.00 | 1.50 | 2.00 |
| 25 | 1.25 | 1.88 | 2.50 |
| 30 | 1.50 | 2.25 | 3.00 |
| 40 | 2.00 | 3.00 | 4.00 |
| 50 | 2.50 | 3.75 | 5.00 |
| 75 | 3.75 | 5.63 | 7.50 |
| 100 | 5.00 | 7.50 | 10.00 |
How it is computed
Volume = area × depth. 1 m³ = 1,000 L = 1.308 cu yd; a 2 cu ft bag holds 0.057 m³. Bag counts are rounded up. Mulch settles, so buy a little extra for a fresh bed.
FAQ
How deep should mulch be?+
5 to 7.5 cm (2 to 3 in) for most beds; up to 10 cm (4 in) on paths or to smother weeds. Keep it off tree trunks and plant stems.
Is bulk or bagged mulch cheaper?+
Bulk is usually cheaper past about 2 m³ (3 cu yd), even with delivery; bags are easier for small beds.