How Much Topsoil Do I Need?
Depth by purpose
| Job | Depth | Notes |
|---|---|---|
| Top-dressing an existing lawn | 1/4–1/2 in | Any deeper smothers the grass |
| Levelling low spots in a lawn | 1/2–1 in per pass | Build up over several mowings rather than in one go |
| Seeding a new lawn over poor soil | 3–4 in | Enough for roots to establish |
| New planting bed | 6–12 in | Blend with the existing soil below |
| Raised bed, vegetables | 10–18 in | Usually a soil blend, not pure topsoil |
| Filling under sod | 2–3 in | Rake level and firm before laying |
Raised beds: the arithmetic
Raised beds swallow more soil than anyone expects, because the volume is depth times area and depth is large:
| Bed | Depth | Cubic feet | Cubic yards | 1 cu ft bags |
|---|---|---|---|---|
| 4 x 4 ft | 12 in | 16 | 0.59 | 16 |
| 4 x 8 ft | 12 in | 32 | 1.19 | 32 |
| 4 x 8 ft | 18 in | 48 | 1.78 | 48 |
| 2 x 8 ft | 10 in | 13.3 | 0.49 | 14 |
At bagged prices, a single 4 x 8 ft bed 12 in deep is thirty-something bags — this is the classic case where bulk delivery wins even though the project feels small. It is also why many people fill the bottom third with coarse organic material and reserve the purchased blend for the top.
Weight is the constraint, not volume
Topsoil runs about 2,200 lb per cubic yard — roughly three times shredded hardwood mulch, and more when wet. Practical consequences:
- A half-ton pickup rated around 1,000–1,500 lb of payload is a one-cubic-yard-at-a-time vehicle for soil, or less.
- A wheelbarrow holds about 3 cubic feet, so one cubic yard is nine barrow loads at roughly 240 lb each.
- Bulk delivery is usually the right answer above about a cubic yard, purely on handling.
Set the material to topsoil in the mulch and soil calculator and it reports the weight alongside the volume, which is the number that decides how the material gets from the yard to the bed.
Topsoil, garden soil, compost: not interchangeable
| Product | What it is | Use for |
|---|---|---|
| Screened topsoil | Mineral soil, screened, variable quality | Bulk filling, levelling, under sod |
| Garden or raised bed soil | Blend of soil, compost and aggregate | Filling beds where you will plant directly |
| Compost | Decomposed organic matter, no mineral content | Amending and top-dressing, not filling on its own |
| Fill dirt | Subsoil, no organic matter | Structural filling and grading only — nothing grows well in it |
Filling a raised bed entirely with compost gives a bed that shrinks dramatically and holds too much water; filling it with cheap fill dirt gives a bed nothing grows in. A blend is what you want, and it is worth asking a bulk supplier exactly what is in their "garden mix".
Ordering advice
- Measure the area with the square footage calculator if the bed is not a simple rectangle.
- Get the volume and weight from the mulch and soil calculator at your intended depth.
- Order about 10% over for settling — freshly placed soil compacts noticeably after the first watering and rain.
- Ask where the truck can dump, and whether the material will be dry enough to barrow. Wet clay-heavy topsoil is far harder work than the volume suggests.
Get the cubic yards, the bag count and the approximate weight for a bed at any depth — and see straight away whether bagged or bulk delivery is the cheaper way to buy it.
Frequently asked questions
How much does a yard of topsoil cover?
About 108 square feet at 3 inches deep, 324 square feet at 1 inch, and 27 square feet at 12 inches. Coverage depends only on depth.
How much topsoil do I need for a 4x8 raised bed?
About 32 cubic feet, or 1.2 cubic yards, for a 12 inch depth — roughly 32 of the 1 cubic foot bags. At 18 inches deep it is 48 cubic feet, close to 1.8 cubic yards.
How much does a cubic yard of topsoil weigh?
Roughly 2,200 pounds dry, and more when wet — about three times the weight of shredded hardwood mulch. That is close to or beyond the payload of a half-ton pickup, so haul soil one cubic yard at a time.
Can I fill a raised bed with compost alone?
Not ideally. Pure compost shrinks a great deal as it settles and holds too much water. A blend of topsoil and compost, or a purpose-made raised bed mix, gives better structure and stable volume.
- How Deep Should Mulch Be?
- Bulk or Bagged Mulch: Which Is Actually Cheaper?
- When Should You Mulch? Spring, Fall, and Why Timing Matters
- Mulch Types Compared: Hardwood, Bark, Cedar, Straw and Rubber