Soil for a 3x8 Raised Bed 12 Inches Deep
A raised bed 3 by 8 feet and 12 inches tall holds 24.0 cubic feet. How much soil for a 3x8 raised bed 12 inches deep in bags: 12 two-cubic-foot bags. In bulk: about 0.89 cubic yards.
Volume and tonnage calculator →The math
- Volume: 3 × 8 × (12 ÷ 12) = 24.0 cu ft.
- Cubic yards: 24.0 ÷ 27 = 0.89 yd³.
- Bags: 24.0 ÷ 2 = 12 bags (2 cu ft), or ÷ 1.5 = 16 bags (1.5 cu ft).
The topsoil calculator handles any bed size.
Related: Soil for a 3x8 Raised Bed 18 Inches Deep
Soil for a 3x8 bed at other depths
| Depth | Cubic feet | Cubic yards | 2 cu ft bags |
|---|---|---|---|
| 6 in | 12.0 | 0.44 | 6 |
| 8 in | 16.0 | 0.59 | 8 |
| 10 in | 20.0 | 0.74 | 10 |
| 12 in | 24.0 | 0.89 | 12 |
| 18 in | 36.0 | 1.33 | 18 |
| 24 in | 48.0 | 1.78 | 24 |
When bulk soil pays off
Bulk soil is usually cheaper per cubic yard than bags once you pass roughly 1 yard. At 0.89 yards, bags are simpler. Fill several beds at once to make a delivery worthwhile.
Related: Soil for a 4x10 Raised Bed 12 Inches Deep
A good raised bed mix
Many gardeners blend topsoil with compost, around 50 to 60 percent topsoil. The compost adds nutrients and keeps the mix loose. Bagged potting soil alone is light and can dry out fast in a deep bed.
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.
Delivery and spreading
Ask the supplier where the truck can safely dump without crossing soft lawn or septic fields. Cover the pile if rain is coming. Spread with a flat shovel and a landscape rake, working from the far end back toward the pile.
Common mistakes
Buying by the bag for a large area is the classic error: dozens of bags cost far more than a bulk yard. Another is skipping compost or using unscreened soil full of clods and roots. Spreading soil when it is soaking wet compacts it and makes it hard for roots and water to move.
Questions people ask
How many bags of soil for a 3x8 raised bed?
About 12 bags of 2 cubic feet at 12 inches deep.
How many cubic feet in a 3x8x12 inch bed?
24.0 cubic feet.
How many yards of soil for a 3x8 raised bed?
About 0.89 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
- How Much Does a Yard of Topsoil Cover?
- How Many Bags of Topsoil in a Yard? Size Chart
- Fill Dirt vs Topsoil: Differences, Uses and Tons to Order
- How Much Does a Yard of Dirt Weigh? Topsoil, Fill, Clay
- Soil for a 3x6 Raised Bed 12 Inches Deep
- Soil for a 3x6 Raised Bed 18 Inches Deep
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