Garden Guide
How Much Soil for a 4x8 Raised Bed?
A 4x8 raised bed has 32 square feet of growing area. The soil amount depends on depth, not just bed size.
Table of Contents
Quick Answer
For a 4x8 raised bed, plan on 16 cubic feet at 6 inches deep, 21.3 cubic feet at 8 inches, or 32 cubic feet at 12 inches. Use the Raised Bed Soil Calculator if your bed depth or dimensions are different.
| Bed depth | Soil volume | Approx. cubic yards | 2 cu ft bags |
|---|---|---|---|
| 6 in | 16 cu ft | 0.59 cu yd | 8 bags |
| 8 in | 21.3 cu ft | 0.79 cu yd | 11 bags |
| 10 in | 26.7 cu ft | 0.99 cu yd | 14 bags |
| 12 in | 32 cu ft | 1.19 cu yd | 16 bags |
| 18 in | 48 cu ft | 1.78 cu yd | 24 bags |
| 24 in | 64 cu ft | 2.37 cu yd | 32 bags |
Formula
Multiply length by width by depth in feet: 4 x 8 x depth in feet = cubic feet.
Example: a 12 inch deep bed is 1 foot deep, so 4 x 8 x 1 = 32 cubic feet.
Buying Soil
Buy slightly more if the bed is new, because soil settles after watering. A 5% to 10% buffer is usually enough.
For a productive vegetable bed, use a raised bed mix or blend topsoil with compost. Avoid filling the whole bed with dense native clay.
- Use 6 to 8 inches for shallow greens and herbs.
- Use 10 to 12 inches for most vegetables.
- Use 18 inches or more for deep-rooted crops if the bed sits on hard ground.
FAQ
How Much Soil for a 4x8 Raised Bed? FAQ
How many bags of soil for a 4x8 raised bed?
At 12 inches deep, a 4x8 bed needs 32 cubic feet, or about 16 bags if each bag contains 2 cubic feet.
How much soil for a 4x8 raised bed 12 inches deep?
You need 32 cubic feet, which is about 1.19 cubic yards.
How deep should soil be in a raised bed?
Most vegetables grow well with 10 to 12 inches of soil. Shallow herbs and greens can use less, while root crops benefit from more.
Should I round up soil for a raised bed?
Yes. Round up by 5% to 10% for settling, uneven fill, and spillage.
Can I use garden soil in a raised bed?
Pure garden soil can compact. Mix it with compost and lighter material, or use a raised bed mix.
What calculator should I use for other bed sizes?
Use the Raised Bed Soil Calculator to enter custom length, width, and depth.