How Much Soil for a 4x8 Raised Bed?
Material needed
0.99 cubic yards
A 4 by 8 bed filled to 10 inches, topsoil at roughly 2,200 lb per cubic yard.
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How that number is worked out
These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.
- Bed area32 sq ft
- Depth10 in
- MaterialTopsoil
Material needed0.99 cubic yards
| Volume | 26.7 cu ft |
|---|---|
| Cubic yards | 0.99most yards sell in half yard steps |
| Order in half yards | 1 cu yd |
| 2 cu ft bags, if bagging it | 14 |
| Approximate weight | 2,173 lb (1.09 tons) |
The material list this produces
| Material, cubic yards | 1 |
|---|---|
| Landscape fabric, sq ft | 32 |
| Edging, linear ft | 23 |
Fill depth compared
Most kit beds are 10 or 12 inches tall and get filled an inch below the rim. Here is the same bed at each of the usual depths.
| Fill depth | Material needed | Order in half yards |
|---|---|---|
| 6 in | 0.59 cubic yards | 1 cu yd |
| 8 in | 0.79 cubic yards | 1 cu yd |
| 10 in | 0.99 cubic yards | 1 cu yd |
| 12 in | 1.19 cubic yards | 1.5 cu yd |
What else matters here
Four by eight is the standard kit size for a reason that has nothing to do with lumber. Four feet is about as far as two arms can reach across from opposite sides, so nobody ever has to step into the bed and compact the soil they just paid for.
At ten inches this bed takes almost exactly one cubic yard, which is the crossover point. Fourteen bags of garden soil at retail usually costs roughly double a yard delivered, and it is fourteen plastic bags to open, empty and get rid of.
A full yard of damp soil is over a ton. That is not a half ton pickup load and it is not something to move in a wheelbarrow without a plan, so have the delivery dropped as close to the bed as the truck can reach.
What this calculator assumes
- Three inches is the usual mulch depth. Two is thin and will not hold weeds down, four starts to smother shallow roots and holds water against trunks.
- Weights are approximate and vary with moisture: mulch about 800 lb per cubic yard, topsoil 2200, gravel 2800, sand 2700.
- Bagged material is sold in 2 cubic foot bags, and there are 13.5 of those in a cubic yard.
Questions people ask
How many cubic yards of soil for a 4x8 raised bed?
About one cubic yard at a 10 inch fill, or 26.7 cubic feet. At 12 inches it is closer to 1.2 yards.
How many bags of soil for a 4x8 raised bed?
About 14 bags at 2 cubic feet each for a 10 inch fill. Bulk is usually half the price at this volume.
Can I fill the bottom with something cheaper?
Partly. Filling the bottom few inches with logs, branches or coarse wood chips is a real technique and it works, but the bed will sink noticeably in the first two seasons as that layer breaks down.
The mulch and gravel calculator takes any dimensions you like and hands back the same list.