Soil for a 3x6 Raised Bed 18 Inches Deep
A raised bed 3 by 6 feet and 18 inches tall holds 27.0 cubic feet. How much soil for a 3x6 raised bed 18 inches deep in bags: 14 two-cubic-foot bags. In bulk: about 1.00 cubic yards.
Volume and tonnage calculator →The math
- Volume: 3 × 6 × (18 ÷ 12) = 27.0 cu ft.
- Cubic yards: 27.0 ÷ 27 = 1.00 yd³.
- Bags: 27.0 ÷ 2 = 14 bags (2 cu ft), or ÷ 1.5 = 18 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 3x6 bed at other depths
| Depth | Cubic feet | Cubic yards | 2 cu ft bags |
|---|---|---|---|
| 6 in | 9.0 | 0.33 | 5 |
| 8 in | 12.0 | 0.44 | 6 |
| 10 in | 15.0 | 0.56 | 8 |
| 12 in | 18.0 | 0.67 | 9 |
| 18 in | 27.0 | 1.00 | 14 |
| 24 in | 36.0 | 1.33 | 18 |
Bags or bulk?
This bed is big enough that a bulk load of garden mix usually beats bags. 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
A good raised bed mix
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
New soil settles, often by 10 to 20 percent in the first season. Overfill slightly or plan to top up with compost next spring. Tall beds can be partly filled with logs or branches at the bottom to save soil (a hugelkultur approach).
Measuring accurately
Walk the area with a tape and sketch it. Break odd shapes into rectangles and circles. If you are topping up an existing bed or lawn, measure only the new depth, since adding a full depth on top of existing soil overbuys.
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.
Questions people ask
How many bags of soil for a 3x6 raised bed?
About 14 bags of 2 cubic feet at 18 inches deep.
How many cubic feet in a 3x6x18 inch bed?
27.0 cubic feet.
How many yards of soil for a 3x6 raised bed?
About 1.00 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 3x3 Raised Bed 12 Inches Deep
- Soil for a 3x6 Raised Bed 12 Inches Deep
As an Amazon Associate, AsphaltTons.com earns from qualifying purchases. Product links below are sponsored.