Soil for a 4×12 bed at different depths
| Soil depth | Cubic feet | Cubic yards | 1.5 cu ft bags | 2 cu ft bags |
|---|---|---|---|---|
| 6 in | 24 | 0.89 | 16 | 12 |
| 8 in | 32 | 1.19 | 22 | 16 |
| 10 in | 40 | 1.48 | 27 | 20 |
| 11 in | 44 | 1.63 | 30 | 22 |
| 12 in | 48 | 1.78 | 32 | 24 |
| 18 in | 72 | 2.67 | 48 | 36 |
| 24 in | 96 | 3.56 | 64 | 48 |
Building with lumber? A single 2×12 gives about 11 inches of soil depth, two stacked 2×6s also give 11 inches.
Planning this bed
At 4 ft wide you can reach the center from both sides without stepping on the soil — that keeps it loose. The bed has 48 sq ft of growing space. Expect the soil to settle 10–20% in the first season, so keep a few bags of compost to top it up.
The math
Common questions
How many bags of soil for a 4x12 raised bed?
32 bags of 1.5 cu ft for 12 inches deep, or 16 bags for 6 inches.
How many cubic yards for a 4x12 raised bed?
1.78 cubic yards at 12 inches deep.
Want the full method, tips and other sizes? See the raised bed soil calculator guide.