AsphaltTons.com — asphalt tonnage calculator

Soil for a 3x6 Raised Bed 12 Inches Deep

A raised bed 3 by 6 feet and 12 inches tall holds 18.0 cubic feet. How much soil for a 3x6 raised bed 12 inches deep in bags: 9 two-cubic-foot bags. In bulk: about 0.67 cubic yards.

Volume and tonnage calculator →

The math

  1. Volume: 3 × 6 × (12 ÷ 12) = 18.0 cu ft.
  2. Cubic yards: 18.0 ÷ 27 = 0.67 yd³.
  3. Bags: 18.0 ÷ 2 = 9 bags (2 cu ft), or ÷ 1.5 = 12 bags (1.5 cu ft).

The topsoil calculator handles any bed size.

Soil for a 3x6 bed at other depths

DepthCubic feetCubic yards2 cu ft bags
6 in9.00.335
8 in12.00.446
10 in15.00.568
12 in18.00.679
18 in27.01.0014
24 in36.01.3318

When bulk soil pays off

For a single bed this size, bagged mix keeps things tidy. Many yards sell a blended raised-bed mix of topsoil and compost by the yard.

What to fill it with

A common home mix is roughly 60 percent topsoil and 40 percent compost, or equal parts topsoil, compost and a drainage material. Avoid filling with plain clay fill dirt, which packs hard.

Settling

Expect the bed to sink a few inches as the soil settles and organic matter breaks down. Mound it a little at first and water it in before planting. Line the bottom with cardboard to smother grass instead of digging it out.

Timing the job

Plan deliveries for a dry stretch so the pile and the ground are workable. Early spring mulching suppresses weeds before they sprout, while fall soil work gives beds time to settle before planting.

Checking quality

Good bulk soil is dark, crumbly and free of trash, large rocks and weed roots. Ask whether it is screened and whether compost is blended in. If possible, look at the pile before ordering or ask for a sample.

Questions people ask

How many bags of soil for a 3x6 raised bed?

About 9 bags of 2 cubic feet at 12 inches deep.

How many cubic feet in a 3x6x12 inch bed?

18.0 cubic feet.

How many yards of soil for a 3x6 raised bed?

About 0.67 cubic yards at 12 inches deep.

What soil mix is best for raised beds?

Topsoil blended with compost, roughly 60/40, is a common starting point.

Will raised bed soil settle?

Yes, often 10 to 20 percent in the first season.

Related guides

Open the volume and tonnage calculator → Asphalt tonnage calculator →

As an Amazon Associate, AsphaltTons.com earns from qualifying purchases. Product links below are sponsored.

Related answers