How much soil do I need for a 4×12 raised bed?
A 4 × 12 ft raised bed filled 12 inches deep holds 48 cubic feet, so buy 52.8 cubic feet of soil to allow for settling. That is 36 bags of 1.5 cubic feet, 27 bags of 2 cubic feet, or 1.96 cubic yards in bulk, and it weighs about 3,960 lb. An 8 inch bed needs 35.2 cubic feet (24 bags); an 18 inch bed, 79.2.
Soil for a 4×12 raised bed by depth
| Soil depth | Cubic feet (10% extra) | 1.5 cu ft bags | 2 cu ft bags | Cubic yards |
|---|---|---|---|---|
| 6 in | 26.4 | 18 | 14 | 0.98 |
| 8 in | 35.2 | 24 | 18 | 1.30 |
| 12 in | 52.8 | 36 | 27 | 1.96 |
| 18 in | 79.2 | 53 | 40 | 2.93 |
For one 4 × 12 ft bed. Multiply by the number of beds, or change the count in the calculator below.
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Mix recipe for a 4×12 bed, 12 inches deep
- Classic 60/30/10: 31.7 cubic feet of topsoil, 15.8 of compost, and 5.3 of perlite, vermiculite, or pine bark fines. Cheapest per cubic foot when the topsoil comes in bulk.
- Equal thirds (Square Foot Gardening): 17.6 cubic feet each of blended compost, peat or coir, and coarse vermiculite. Light and fast-draining; the vermiculite makes it the costliest option.
- Bagged raised bed mix: 36 bags of 1.5 cubic feet. No mixing, highest price.
- Hugelkultur: fill the bottom 6 inches with logs and branches and buy only 26.4 cubic feet of soil for the top.
Whatever the mix, top the bed with 2 inches of compost each spring; the soil level drops a couple of inches a year as organic matter breaks down. See the topsoil calculator for bulk soil and the plant spacing calculator for how many plants fit in 48 square feet.
What it costs to fill a 4×12 bed
Bagged raised bed mix at $8 to $12 per 1.5 cubic foot bag puts the 12 inch fill at $288 to $432. Mixing your own from bagged topsoil ($2 to $3 per bag), compost ($5 to $8), and perlite brings it to roughly $132 to $211. Bulk garden blend at $40 to $70 per cubic yard is $78 to $137 plus a $50 to $100 delivery fee, clearly the better deal at this volume. The bed frame itself, in cedar 2 × 6 or 2 × 12 boards, adds $80 to $160 for a 12 inch tall frame.
Common questions
How many bags of soil for a 4x12 raised bed?
36 bags of 1.5 cubic feet or 27 bags of 2 cubic feet for a 12 inch depth. At 8 inches it is 24 and 18 bags; at 6 inches, 18 and 14.
How many cubic feet of soil for a 4x12 bed?
48 cubic feet per foot of depth. A 12 inch fill is 48 cubic feet, or 52.8 with 10 percent for settling; an 18 inch fill is 79.2 cubic feet.
How many cubic yards of soil for a 4x12 raised bed?
1.96 cubic yards at 12 inches deep or 2.93 at 18 inches. There are 27 cubic feet in a yard, so most single beds take less than one yard.