Soil for a 4x4 Raised Bed 18 Inches Deep
A raised bed 4 by 4 feet and 18 inches tall holds 24.0 cubic feet. How much soil for a 4x4 raised bed 18 inches deep in bags: 12 two-cubic-foot bags. In bulk: about 0.89 cubic yards.
Volume and tonnage calculator →The math
- Volume: 4 × 4 × (18 ÷ 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 4x8 Raised Bed 18 Inches Deep
Soil for a 4x4 bed at other depths
| Depth | Cubic feet | Cubic yards | 2 cu ft bags |
|---|---|---|---|
| 6 in | 8.0 | 0.30 | 4 |
| 8 in | 10.7 | 0.40 | 6 |
| 10 in | 13.3 | 0.49 | 7 |
| 12 in | 16.0 | 0.59 | 8 |
| 18 in | 24.0 | 0.89 | 12 |
| 24 in | 32.0 | 1.19 | 16 |
Bags or bulk?
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.
Related: Soil for a 4x12 Raised Bed 18 Inches Deep
What to fill it with
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.
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.
Weight and hauling
A cubic yard of soil can weigh a ton or more, and mulch roughly a quarter to half of that depending on moisture. Check your vehicle’s payload before hauling, and keep trailer loads within the rated capacity.
Questions people ask
How many bags of soil for a 4x4 raised bed?
About 12 bags of 2 cubic feet at 18 inches deep.
How many cubic feet in a 4x4x18 inch bed?
24.0 cubic feet.
How many yards of soil for a 4x4 raised bed?
About 0.89 cubic yards at 18 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 4x4 Raised Bed 10 Inches Deep
- Soil for a 4x4 Raised Bed 12 Inches Deep
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