How much soil do I need for a 3×6 raised bed?
A 3 × 6 ft raised bed filled 12 inches deep holds 18 cubic feet, so buy 19.8 cubic feet of soil to allow for settling. That is 14 bags of 1.5 cubic feet, 10 bags of 2 cubic feet, or 0.73 cubic yards in bulk, and it weighs about 1,485 lb. An 8 inch bed needs 13.2 cubic feet (9 bags); an 18 inch bed, 29.7.
Soil for a 3×6 raised bed by depth
| Soil depth | Cubic feet (10% extra) | 1.5 cu ft bags | 2 cu ft bags | Cubic yards |
|---|---|---|---|---|
| 6 in | 9.9 | 7 | 5 | 0.37 |
| 8 in | 13.2 | 9 | 7 | 0.49 |
| 12 in | 19.8 | 14 | 10 | 0.73 |
| 18 in | 29.7 | 20 | 15 | 1.10 |
For one 3 × 6 ft bed. Multiply by the number of beds, or change the count in the calculator below.
Change the numbers
The calculator below is preset for this size. Adjust anything and the results update instantly.
Mix recipe for a 3×6 bed, 12 inches deep
- Classic 60/30/10: 11.9 cubic feet of topsoil, 5.9 of compost, and 2.0 of perlite, vermiculite, or pine bark fines. Cheapest per cubic foot when the topsoil comes in bulk.
- Equal thirds (Square Foot Gardening): 6.6 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: 14 bags of 1.5 cubic feet. No mixing, highest price.
- Hugelkultur: fill the bottom 6 inches with logs and branches and buy only 9.9 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 18 square feet.
What it costs to fill a 3×6 bed
Bagged raised bed mix at $8 to $12 per 1.5 cubic foot bag puts the 12 inch fill at $112 to $168. Mixing your own from bagged topsoil ($2 to $3 per bag), compost ($5 to $8), and perlite brings it to roughly $50 to $79. Bulk garden soil at $40 to $70 per cubic yard would cost $40 to $70 plus delivery, which only pays off if you are filling several beds at once. The bed frame itself, in cedar 2 × 6 or 2 × 12 boards, adds $45 to $90 for a 12 inch tall frame.
Common questions
How many bags of soil for a 3x6 raised bed?
14 bags of 1.5 cubic feet or 10 bags of 2 cubic feet for a 12 inch depth. At 8 inches it is 9 and 7 bags; at 6 inches, 7 and 5.
How many cubic feet of soil for a 3x6 bed?
18 cubic feet per foot of depth. A 12 inch fill is 18 cubic feet, or 19.8 with 10 percent for settling; an 18 inch fill is 29.7 cubic feet.
How many cubic yards of soil for a 3x6 raised bed?
0.73 cubic yards at 12 inches deep or 1.10 at 18 inches. There are 27 cubic feet in a yard, so most single beds take less than one yard.