What does 202.69 cubic yards of walnut hull mulch mean?
It means a 19900 square foot bed, once the 10% waste allowance is added, needs 21,890.00 square feet of cover at 3 inches deep — 5,472.50 cubic feet, which is 202.69 cubic yards. Because mulch is sold by the whole yard, you order 203 cubic yards: the exact figure sits 0.31 yards below the next whole yard, so the order carries 0.31 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 135.12 yards, and at 4 inches it would need 270.25 yards.
Output · formula · meaning
| Output | Formula | What it means |
|---|
| Area needed | area × (1 + waste ÷ 100) | 21,890.00 sq ft — 19900 × 1.10. |
| Volume in cubic feet | area needed × depth ÷ 12 | 5,472.50 cubic feet — 21,890.00 × 3 ÷ 12. |
| Exact volume | area needed × depth ÷ 324 | 202.69 cubic yards — 21,890.00 × 3 ÷ 324. |
| Order quantity | round exact volume up to a whole yard | 203 cubic yards — the next whole yard above 202.69. |
| 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) | 19900 sq ft — 202.69 × 324 ÷ 3 ÷ 1.10, rounded. |
| Depth behind a target volume | area needed × depth ÷ 324, solved for depth | 3 inches — the depth that turns 21,890.00 sq ft into 202.69 yards. |
| Waste behind a target volume | target volume × 324 ÷ depth ÷ area − 1, as a percent | 10% — the allowance that turns 19900 sq ft into 21,890.00 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: walnut hulls are thick and chunky, so they lock into a heavy layer that holds moisture well, but even a heavy layer shifts at the edges and the thin spots need topping up through the season. Third, do not skip the waste allowance on walnut hull: even well-laid walnut hulls scatter 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 203 yards carries 0.31 yards of headroom, which covers ordinary spillage on a bed like this one. The walnut hulls themselves are hulls left after the walnut harvest — the mulch comes from the orchard, not from timber.
Worked example
Area 19900 sq ft, depth 3 inches, waste 10%. Area needed: 19900 × 1.10 = 21,890.00 sq ft. Exact volume: 21,890.00 × 3 ÷ 324 = 202.69 cubic yards. Order: round 202.69 up to 203 cubic yards. Drop the waste to 0% and the exact volume falls to 184.26 yards, order 185; raise the waste to 5% and it is 193.47 yards, order 194; raise it to 15% and it is 211.90 yards, order 212. Drop the depth to 2 inches and it falls to 135.12 yards, order 136; raise it to 4 inches and it climbs to 270.25 yards, order 271. Depth moves the answer faster than waste does, because every inch adds a full layer across the whole bed.
Walnut 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 19900 square foot bed at 3-inch depth with 0% waste gives 184.26 cubic yards exact, order 185 cubic yards. The same bed at 2-inch depth with 10% waste gives 135.12 cubic yards exact, order 136 cubic yards. A 19800 square foot bed at 3-inch depth with 10% waste gives 201.67 cubic yards exact, order 202 cubic yards. The same bed at 4-inch depth with 10% waste gives 270.25 cubic yards exact, order 271 cubic yards. Each branch changes exactly one input, so the difference from 202.69 isolates that input.
The reverses, worked backwards
The area behind 202.69 cubic yards is 19900 sq ft: at 19800 sq ft the figures are 201.67 cubic yards exact, order 202 cubic yards, and at 20000 sq ft they are 203.70 cubic yards exact, order 204 cubic yards. The depth behind 202.69 cubic yards is 3 inches: at 2 inches the figures are 135.12 cubic yards exact, order 136 cubic yards, and at 4 inches they are 270.25 cubic yards exact, order 271 cubic yards — one inch either way moves the order by about 67.56 yards. The waste behind 202.69 cubic yards is 10%: at 5% the figures are 193.47 cubic yards exact, order 194 cubic yards, and at 15% they are 211.90 cubic yards exact, order 212 cubic yards.
What the defaults assume
The defaults assume a flat 19900 square foot bed, a uniform 3-inch layer, and a 10% waste allowance. Real walnut hull beds are rarely simple rectangles: paths and tree trunks eat into the area, and walnut hulls at the edges wash 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 walnut hull: the 19900 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 walnut hull job: the waste column protects the quote, and the order column is the number given to the supplier. A homeowner laying walnut 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 walnut 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 walnut hulls — a supplier may sell only in whole yards or charge extra below a minimum, so confirm the order quantity with the supplier. Black walnut hulls also carry juglone, which can check the growth of juglone-sensitive plants such as tomatoes, so keep this mulch off vegetable beds unless the planting has been checked. This page is a calculation tool, not landscaping advice.
Cite this calculator
Walnut hull mulch 19900 sq ft at 3-inch depth with 10% waste needs 21,890 sq ft, 202.69 cubic yards exact, order 203 yards. Free calculator, plus 16 rows. Source: Bright Side Kit, https://brightoolbox.com/walnut-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 walnut hull mulch really be?
Three inches is the standard bed layer on this page, and 2 inches suit paths and top-ups. Walnut hulls are thick and chunky, so a 3-inch spread holds its depth well, though the pieces still shift at the edges; if thin spots appear, top them up rather than re-laying the whole bed.
Does walnut hull mulch introduce weed seeds?
Walnut 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 203 yards when the exact figure is 202.69?
Because mulch is sold by the whole yard, and 202.69 rounds up to 203 — the order carries 0.31 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. Walnut hulls break down slowly, so use the walnut hull rows for walnut hull and the matching chart for stone or wood chips.