Cubic feet = Length × Width × Depth (all in feet). Cubic yards = Cubic feet ÷ 27. A 4×8 bed at 12" deep = 4×8×1 = 32 cu ft = 1.2 cubic yards. Add 10-15% for settling.
- Formula: L × W × D (feet) ÷ 27 = Cubic yards
- 1 cubic yard = 27 cubic feet
- Add 10-15% for settling over time
- Soil settles 1-2" after watering
- May need to top off after first season
| Bed Size | 6" Deep | 12" Deep | 18" Deep |
|---|---|---|---|
| 4×4 ft | 0.3 cu yd (8 cu ft) | 0.6 cu yd (16 cu ft) | 0.9 cu yd (24 cu ft) |
| 4×8 ft | 0.6 cu yd (16 cu ft) | 1.2 cu yd (32 cu ft) | 1.8 cu yd (48 cu ft) |
| 4×12 ft | 0.9 cu yd (24 cu ft) | 1.8 cu yd (48 cu ft) | 2.7 cu yd (72 cu ft) |
| 3×6 ft | 0.3 cu yd (9 cu ft) | 0.7 cu yd (18 cu ft) | 1.0 cu yd (27 cu ft) |