How Much Topsoil for a Garden Bed?
Quick Answer
A 10×10 garden bed filled 6 inches deep needs 1.85 cubic yards of topsoil, which is about 50 one-cubic-foot bags. For depth, use 6 inches for flower beds and 12 inches for raised vegetable beds.
- 10×10 bed at 6 in: 1.85 cubic yards (~50 one-cu-ft bags)
- Use 6 inches for flowers, 12 inches for vegetables
- Bulk topsoil is far cheaper than bags past ~1 cubic yard
- Topsoil weighs roughly 1.1 tons per cubic yard
Formula
Multiply the bed area by depth in inches, then divide by 324 to get cubic yards. To count bags, multiply area by depth in feet to get cubic feet, then divide by the bag size (often 0.75 or 1 cubic foot).
Step-by-Step Calculation
- 1
Bed area
10 × 10 = 100 square feet
- 2
Volume at 6 inches
(100 × 6) ÷ 324 = 1.85 cubic yards
- 3
Cubic feet for bags
100 × 0.5 = 50 cubic feet
- 4
One-cu-ft bags
50 ÷ 1 = 50 bags
Topsoil by Bed Size and Depth
| Bed Size | 3 in Depth | 6 in Depth | 12 in Depth |
|---|---|---|---|
| 4×8 (32 sq ft) | 0.30 cu yd | 0.59 cu yd | 1.19 cu yd |
| 8×8 (64 sq ft) | 0.59 cu yd | 1.19 cu yd | 2.37 cu yd |
| 10×10 (100 sq ft) | 0.93 cu yd | 1.85 cu yd | 3.70 cu yd |
| 10×20 (200 sq ft) | 1.85 cu yd | 3.70 cu yd | 7.41 cu yd |
Bulk topsoil runs about $15–$40 per cubic yard delivered, far cheaper per volume than bagged soil once you need more than a yard.
Frequently Asked Questions
How deep should topsoil be for a garden bed?
Use about 6 inches for flower beds and lawns, and 10 to 12 inches for raised vegetable beds so roots have room. Deeper beds hold moisture better and support a wider range of plants.
How many bags of topsoil in a cubic yard?
A cubic yard is 27 cubic feet, so it equals 27 one-cubic-foot bags or 36 of the common 0.75-cubic-foot bags. Buying in bulk is far cheaper once you need more than about a yard.
Is topsoil the same as garden soil?
No. Topsoil is the base — screened natural soil. Garden or raised-bed soil is topsoil blended with compost and organic matter for planting. Many beds use a mix: topsoil for volume plus compost for fertility.