Mulch & Mortar

How much soil do I need for a 4×4 raised bed?

A 4 × 4 ft raised bed filled 12 inches deep holds 16 cubic feet, so buy 17.6 cubic feet of soil to allow for settling. That is 12 bags of 1.5 cubic feet, 9 bags of 2 cubic feet, or 0.65 cubic yards in bulk, and it weighs about 1,320 lb. An 8 inch bed needs 11.7 cubic feet (8 bags); an 18 inch bed, 26.4.

Soil for a 4×4 raised bed by depth

Soil depthCubic feet (10% extra)1.5 cu ft bags2 cu ft bagsCubic yards
6 in8.8650.33
8 in11.7860.43
12 in17.61290.65
18 in26.418140.98

For one 4 × 4 ft bed. Multiply by the number of beds, or change the count in the calculator below.

Change the numbers

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Fill to about 2 in below the top of the frame.
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Mix recipe for a 4×4 bed, 12 inches deep

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 16 square feet.

What it costs to fill a 4×4 bed

Bagged raised bed mix at $8 to $12 per 1.5 cubic foot bag puts the 12 inch fill at $96 to $144. Mixing your own from bagged topsoil ($2 to $3 per bag), compost ($5 to $8), and perlite brings it to roughly $44 to $70. 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 $40 to $80 for a 12 inch tall frame.

Common questions

How many bags of soil for a 4x4 raised bed?

12 bags of 1.5 cubic feet or 9 bags of 2 cubic feet for a 12 inch depth. At 8 inches it is 8 and 6 bags; at 6 inches, 6 and 5.

How many cubic feet of soil for a 4x4 bed?

16 cubic feet per foot of depth. A 12 inch fill is 16 cubic feet, or 17.6 with 10 percent for settling; an 18 inch fill is 26.4 cubic feet.

How many cubic yards of soil for a 4x4 raised bed?

0.65 cubic yards at 12 inches deep or 0.98 at 18 inches. There are 27 cubic feet in a yard, so most single beds take less than one yard.

Other sizes