How much garden soil for a bed
cubic feet = length (ft) × width (ft) × depth (in) ÷ 12 cubic yards = cubic feet ÷ 27
Worked example (the default): a 16 × 4 ft border, 6 inches of new garden soil.
- Area: 16 × 4 = 64 square feet
- Volume: 64 × 6 ÷ 12 = 32 cubic feet = 1.19 cubic yards
- With 10% extra: 35.2 cubic feet = 1.30 cubic yards
- In bags: 36 bags of 1 cubic foot, 24 bags of 1.5 cubic feet or 18 bags of 2 cubic feet
For a curved border, switch the area shape to Circle for round beds, or break the border into a few rectangles and add them.
How deep to go
| Job | New garden soil | Notes |
|---|---|---|
| New vegetable bed on lawn or compacted ground | 6–8 in on top | Loosen the ground underneath first. |
| New bed where the soil is already workable | 2–4 in, mixed in | Fork it into the top 6–8 in. |
| Raising a low, wet bed | 6–12 in | Lifts roots out of soggy ground. |
| Refreshing an existing bed | 1–2 in | Compost alone often does this job; see the compost calculator. |
| Planting holes for trees and shrubs | little or none | Many extension services suggest backfilling with the native soil. |
Garden soil per 100 square feet
| Depth | Cubic feet | Cubic yards | 1.5 cu ft bags |
|---|---|---|---|
| 2 in | 16.7 | 0.62 | 12 |
| 3 in | 25 | 0.93 | 17 |
| 4 in | 33.3 | 1.23 | 23 |
| 6 in | 50 | 1.85 | 34 |
| 8 in | 66.7 | 2.47 | 45 |
For 250 square feet multiply by 2.5, for 50 square feet by 0.5, and so on.
What “garden soil” means when you buy it
The name is used for two quite different things:
- Bulk garden soil (also called garden mix or planting mix) from a landscape yard is usually screened topsoil blended with compost, sometimes with some sand. It is sold by the yard and is meant to be the soil your plants grow in.
- Bagged garden soil is usually lighter and higher in organic matter. The label generally says it is for mixing into existing ground; it is not the same as potting mix, and it is not meant to fill pots on its own.
Ask the supplier what is in their blend: roughly how much compost, whether it is screened, and whether they can share a soil test. For a side-by-side comparison, see topsoil vs garden soil.
Weight and delivery
Garden soil blends weigh roughly 0.8 to 1.2 tons per cubic yard, less than plain topsoil because compost is lighter. The tons line uses the middle of that range. Wet soil weighs more, so ask the supplier for their figure if you are hauling it yourself.
Bulk deliveries are tipped in one heap, so pick a drop spot close to the bed and put down a tarp if it is going on a lawn or driveway. One cubic yard is about four to five loads of a typical 6-cubic-foot wheelbarrow.
Preparing the ground first
- Clear grass and weeds, or smother them under cardboard for a season.
- Loosen the existing soil with a fork, especially if it is compacted.
- Spread the garden soil in a layer or two, mixing the first layer into the ground below so there isn’t a sharp line between them.
- Rake level, water well, and let it settle for a few days before planting. Top up any low spots.
Results are estimates. Blends, moisture and settling vary, so confirm the quantity with your supplier before ordering.
Questions gardeners ask
- How much garden soil do I need?
- Length × width in feet × depth in inches ÷ 12 gives cubic feet; divide by 27 for cubic yards. A 16 × 4 ft bed with 6 inches of new soil needs 32 cubic feet, about 1.19 cubic yards, plus 10 percent for settling.
- How deep should garden soil be for a new bed?
- On poor or compacted ground, 6 to 8 inches of new soil gives most vegetables and flowers a good root zone. If your existing soil is workable, 2 to 4 inches mixed into the loosened top 6 to 8 inches is often enough.
- What is garden soil?
- In bulk it usually means screened topsoil blended with compost. In bags, garden soil is usually an organic-rich product meant to be mixed into the ground, not used alone in pots.
- Should I put garden soil in the planting hole for trees and shrubs?
- Many extension services advise backfilling tree and shrub holes mostly with the soil you dug out, because very rich backfill can discourage roots from spreading into the surrounding ground.