What does 345.28 cubic yards of soybean hull mulch mean?
It means a 33900 square foot bed, once the 10% waste allowance is added, needs 37,290.00 square feet of cover at 3 inches deep — 9,322.50 cubic feet, which is 345.28 cubic yards. Because mulch is sold by the whole yard, you order 346 cubic yards: the exact figure sits 0.72 yards below the next whole yard, so the order carries 0.72 yards of headroom for spillage and uneven ground. At 3 inches, one cubic yard covers 108.0 square feet, so the same bed at 2 inches would need only 230.19 yards, and at 4 inches it would need 460.37 yards.
Output · formula · meaning
| Output | Formula | What it means |
|---|
| Area needed | area × (1 + waste ÷ 100) | 37,290.00 sq ft — 33900 × 1.10. |
| Volume in cubic feet | area needed × depth ÷ 12 | 9,322.50 cubic feet — 37,290.00 × 3 ÷ 12. |
| Exact volume | area needed × depth ÷ 324 | 345.28 cubic yards — 37,290.00 × 3 ÷ 324. |
| Order quantity | round exact volume up to a whole yard | 346 cubic yards — the next whole yard above 345.28. |
| Coverage per yard | 324 ÷ depth | 108.0 sq ft per yard — 324 ÷ 3. |
| Area behind a target volume | target volume × 324 ÷ depth ÷ (1 + waste ÷ 100) | 33900 sq ft — 345.28 × 324 ÷ 3 ÷ 1.10, rounded. |
| Depth behind a target volume | area needed × depth ÷ 324, solved for depth | 3 inches — the depth that turns 37,290.00 sq ft into 345.28 yards. |
| Waste behind a target volume | target volume × 324 ÷ depth ÷ area − 1, as a percent | 10% — the allowance that turns 33900 sq ft into 37,290.00 sq ft. |
Three things to check before you trust the number
First, measure the bed honestly: length times width for each bed, added together, with L-shaped beds split into rectangles. A guessed area moves the order by the same percentage as the guess. Second, keep the depth honest: soybean hulls are light and papery, so they settle into a soft layer that holds moisture well, but even a firm layer thins as it breaks down and the thin spots need topping up through the season. Third, do not skip the waste allowance on soybean hull: even well-laid soybean hulls blow about at the edges, and spillage and uneven ground still eat into the load, so the 10% allowance is the difference between finishing the bed and running short with the truck already gone. The headline order of 325 yards carries 0.72 yards of headroom, which covers ordinary spillage on a bed like this one. The soybean hulls themselves are hulls left after the soybean harvest — the mulch comes from soybean plants, not from timber.
Worked example
Area 33900 sq ft, depth 3 inches, waste 10%. Area needed: 33900 × 1.10 = 37,290.00 sq ft. Exact volume: 37,290.00 × 3 ÷ 324 = 345.28 cubic yards. Order: round 345.28 up to 346 cubic yards. Drop the waste to 0% and the exact volume falls to 313.89 yards, order 314; raise the waste to 5% and it is 329.58 yards, order 330; raise it to 15% and it is 360.97 yards, order 361. Drop the depth to 2 inches and it falls to 230.19 yards, order 231; raise it to 4 inches and it climbs to 460.37 yards, order 461. Depth moves the answer faster than waste does, because every inch adds a full layer across the whole bed.
Soybean hull mulch lookup table
Every row below applies 10% waste to the area first, then divides by 324: yards = area needed × depth ÷ 324, rounded up to the next whole yard for the order. Find your bed size and depth, read across, and order the last column.
| Area (sq ft) | Depth (inches) | Area needed (sq ft, 10% waste) | Exact (cubic yards) | Order |
|---|
| 300 | 2 | 330.00 | 2.04 | 3 cubic yards |
| 300 | 3 | 330.00 | 3.06 | 4 cubic yards |
| 600 | 2 | 660.00 | 4.07 | 5 cubic yards |
| 600 | 3 | 660.00 | 6.11 | 7 cubic yards |
| 800 | 3 | 880.00 | 8.15 | 9 cubic yards |
| 800 | 4 | 880.00 | 10.86 | 11 cubic yards |
| 1100 | 2 | 1,210.00 | 7.47 | 8 cubic yards |
| 1100 | 3 | 1,210.00 | 11.20 | 12 cubic yards |
| 1300 | 2 | 1,430.00 | 8.83 | 9 cubic yards |
| 1500 | 3 | 1,650.00 | 15.28 | 16 cubic yards |
| 1600 | 3 | 1,760.00 | 16.30 | 17 cubic yards |
| 1600 | 4 | 1,760.00 | 21.73 | 22 cubic yards |
| 1800 | 2 | 1,980.00 | 12.22 | 13 cubic yards |
| 2200 | 3 | 2,420.00 | 22.41 | 23 cubic yards |
| 2600 | 3 | 2,860.00 | 26.48 | 27 cubic yards |
| 3200 | 2 | 3,520.00 | 21.73 | 22 cubic yards |
Every branch, checked
A 33900 square foot bed at 3-inch depth with 0% waste gives 313.89 cubic yards exact, order 314 cubic yards. The same bed at 2-inch depth with 10% waste gives 230.19 cubic yards exact, order 231 cubic yards. A 33800 square foot bed at 3-inch depth with 10% waste gives 344.26 cubic yards exact, order 345 cubic yards. The same bed at 4-inch depth with 10% waste gives 460.37 cubic yards exact, order 461 cubic yards. Each branch changes exactly one input, so the difference from 345.28 isolates that input.
The reverses, worked backwards
The area behind 345.28 cubic yards is 33900 sq ft: at 33800 sq ft the figures are 344.26 cubic yards exact, order 345 cubic yards, and at 34000 sq ft they are 346.30 cubic yards exact, order 347 cubic yards. The depth behind 345.28 cubic yards is 3 inches: at 2 inches the figures are 230.19 cubic yards exact, order 231 cubic yards, and at 4 inches they are 460.37 cubic yards exact, order 461 cubic yards — one inch either way moves the order by about 115.09 yards. The waste behind 345.28 cubic yards is 10%: at 5% the figures are 329.58 cubic yards exact, order 330 cubic yards, and at 15% they are 360.97 cubic yards exact, order 361 cubic yards.
What the defaults assume
The defaults assume a flat 33900 square foot bed, a uniform 3-inch layer, and a 10% waste allowance. Real soybean hull beds are rarely simple rectangles: paths and tree trunks eat into the area, and soybean hulls at the edges blow into the lawn, so measure the planted area only and keep the waste allowance on sloped ground. Zero square feet is the honest edge: 0.00 cubic yards exact, order 0. A depth of zero or below, a negative area, or a negative waste allowance is rejected, because none of them describes a real bed.
Who uses this
A gardener dressing beds and paths with soybean hull: the 33900 square foot headline is a large garden bed or a long drive, and the table covers everything from a 300 square foot border to a 3200 square foot yard. A landscaper quoting a soybean hull job: the waste column protects the quote, and the order column is the number given to the supplier. A homeowner laying soybean hull on a path: the 3-inch rows are the bed depths, and the 2-inch rows are the path depths. A community garden coordinator splitting a bulk delivery: each plot reads its own row, and the orders add up to the truckload.
Accuracy & limitations
The arithmetic is exact for the inputs entered; the judgement is in the inputs. A guessed area, a depth measured before the soybean hulls settle, or a skipped waste allowance will each move the answer by exactly the amount of the error, every load. The model does not include hull washing at the edges, delivery minimums, or the gaps between soybean hulls — a supplier may sell only in whole yards or charge extra below a minimum, so confirm the order quantity with the supplier. Soybean hulls are safe around most garden plants, but a thin fresh layer can scatter in wind, so top up established beds through the season rather than laying one thick layer and leaving it. This page is a calculation tool, not landscaping advice.
Cite this calculator
Soybean hull mulch 33900 sq ft at 3-inch depth with 10% waste needs 37,290 sq ft, 345.28 cubic yards exact, order 346 yards. Free calculator, plus 16 rows. Source: Bright Side Kit, https://brightoolbox.com/soybean-hull-mulch-chart/, accessed 2 November 2026 (2026-11-02).
Frequently asked questions
Why does the table apply waste to the area first?
Because waste is lost cover: spillage, scattering and uneven ground mean you need more covered area than the bed measures. Adding 10% to the area, then converting to yards, keeps the waste in the same units as the bed. Applying it after the conversion gives the same number here, but the area-first order keeps the table readable.
How deep should soybean hull mulch really be?
Three inches is the standard bed layer on this page, and 2 inches suit paths and top-ups. Soybean hulls are light and papery, so a 3-inch spread settles quickly, though the hulls still break down over time; if thin spots appear, top them up rather than re-laying the whole bed.
Does soybean hull mulch introduce weed seeds?
Soybean hulls are organic, so a load can carry a few weed seeds; weeds can still root in the dust and debris that collects on top of it, so use fabric underneath and clear the debris. This calculator prices volume only and does not judge the gardening choice.
What if my bed is not a rectangle?
Split it into rectangles, measure each, and add the areas before entering the total. A circle uses radius times radius times 3.14. Guessing one number for an irregular bed is the most common reason orders come up short.
Why order 346 yards when the exact figure is 345.28?
Because mulch is sold by the whole yard, and 345.28 rounds up to 325 — the order carries 0.72 yards of headroom for spillage and uneven ground. That headroom is the buffer the exact figure does not have.
Can I use this chart for other mulch types?
The volume math is the same for any loose mulch — area, depth and waste convert the same way — but settling and coverage differ by material. Soybean hulls break down quickly, so use the soybean hull rows for soybean hull and the matching chart for stone or wood chips.