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Walnut mulch chart
Put your walnut mulch area, depth and waste in: 550 sq ft at 5-inch depth with 10% waste needs 605.00 sq ft — 9.34 cubic yards exact, order 10.
★ CONSTRUCTION · REFERENCE TABLE #465 · WALNUT MULCH
Walnut Mulch Chart: 550 Sq Ft, 5 Inches, Order 10 Yards
On the defaults — 550 square feet at a 5-inch depth with 10% waste — you need 605.00 square feet of coverage, which is 9.34 cubic yards exact, so order 10 cubic yards. This is reference table #465 — the walnut version, where a dark, slow-breaking shell mulch suits paths and beds that need a long-lived cover — the eucalyptus-mulch-chart page is the eucalyptus version (650 sq ft, 2 inches, order 5 yards), the pine-bark-mulch-chart page is the pine bark version, and the cedar-mulch-chart page is the cedar version.
What does 9.34 cubic yards of walnut mulch mean?
It means 605.00 square feet of coverage at 5 inches deep: the 550 square feet you measured, plus 10% for settling and spreading loss. One cubic yard covers 324 square feet at 1 inch, so at 5 inches one yard covers only 64.8 square feet — that is why even a modest garden path orders several yards. The exact figure is 9.34 yards; you cannot order a fraction of a yard from most suppliers, so the order rounds up to 10. The extra 0.66 yard is not waste — it is the top-up the beds will need as the shells settle and the voids between them close.
Output · formula · meaning
| Output | Formula | What it means |
|---|---|---|
| Needed area | area × (1 + waste ÷ 100) | 605.00 sq ft — 550 × 1.10. |
| Coverage per cubic yard | 324 ÷ depth in inches | 64.8 sq ft per yard — 324 ÷ 5. |
| Exact cubic yards | needed area × depth ÷ 324 | 9.34 — 605.00 × 5 ÷ 324. |
| Order | exact cubic yards rounded up | 10 cubic yards — 9.34 rounded up. |
| Area behind a target order | target yards × 324 ÷ depth ÷ (1 + waste ÷ 100) | 550 sq ft behind 9.34 yards at 5 inches and 10% waste. |
| Depth behind a target order | target yards × 324 ÷ needed area | 5 inches behind 9.34 yards over 605.00 sq ft. |
| Waste behind a target order | (target yards × 324 ÷ depth ÷ area − 1) × 100 | 10% behind 9.34 yards over 550 sq ft at 5 inches. |
Three things to check before you trust the number
First, measure only the beds and paths you will cover: walnut mulch on lawn or bare soil is not mulch, it is litter, and measuring the whole garden overstates the order. Second, depth is installed depth, not settled depth: shells pack down under rain and foot traffic, so a path laid at 5 inches will not stay 5 inches — the 10% waste covers spreading loss, and a top-up after the first rain keeps the depth. Third, walnut shells break down very slowly and contain compounds that some plants dislike: they suit paths and beds of tolerant plants, but a bed of sensitive seedlings may prefer a faster-breaking mulch — check the planting, not just the volume, before ordering by the yard.
Worked example
Area 550 square feet, depth 5 inches, waste 10%. Needed area: 550 × 1.10 = 605.00 square feet. Coverage per yard at 5 inches: 324 ÷ 5 = 64.8 square feet. Exact yards: 605.00 ÷ 64.8 = 9.34. Order: 10 cubic yards. The same area at 3 inches would need 5.60 yards (order 6), and at 2 inches it would need only 3.73 yards (order 4) — depth drives this chart more than area does, because every extra inch multiplies the whole surface.
Walnut mulch lookup table
Every row below is the same formula at 10% waste: needed area is area × 1.10, exact cubic yards are needed area × depth ÷ 324, and the order is the exact figure rounded up. Rows vary in both area and depth, so a shallow small bed and a deep large one can both be read off directly. Find your row, or use the calculator above for any size the table does not list.
| Area (sq ft) | Depth (inches) | Needed area (sq ft) | Exact cubic yards | Order |
|---|---|---|---|---|
| 100 | 3 | 110.00 | 1.02 | 2 cubic yards |
| 200 | 3 | 220.00 | 2.04 | 3 cubic yards |
| 100 | 5 | 110.00 | 1.70 | 2 cubic yards |
| 200 | 5 | 220.00 | 3.40 | 4 cubic yards |
| 300 | 3 | 330.00 | 3.06 | 4 cubic yards |
| 400 | 3 | 440.00 | 4.07 | 5 cubic yards |
| 500 | 5 | 550.00 | 8.49 | 9 cubic yards |
| 550 | 5 | 605.00 | 9.34 | 10 cubic yards |
| 550 | 3 | 605.00 | 5.60 | 6 cubic yards |
| 600 | 5 | 660.00 | 10.19 | 11 cubic yards |
| 700 | 5 | 770.00 | 11.88 | 12 cubic yards |
| 800 | 3 | 880.00 | 8.15 | 9 cubic yards |
| 1000 | 5 | 1100.00 | 16.98 | 17 cubic yards |
| 300 | 5 | 330.00 | 5.09 | 6 cubic yards |
| 400 | 5 | 440.00 | 6.79 | 7 cubic yards |
| 1000 | 3 | 1100.00 | 10.19 | 11 cubic yards |
Every branch, checked
At 0% waste, 550 square feet at 5 inches needs 8.49 yards exact — order 9. At 3 inches with 10% waste, the same area needs 5.60 yards exact — order 6. At 1000 square feet with 5 inches and 10% waste, the order is 16.98 yards exact — order 17. At 400 square feet with 5 inches and 10% waste, the order is 6.79 yards exact — order 7. Each branch changes exactly one input, so the difference from 9.34 isolates that input.
The reverses, worked backwards
The area behind 9.34 yards is 550 square feet: at 500 square feet the figures are 8.49 yards exact — order 9, and at 600 square feet they are 10.19 yards exact — order 11. The depth behind 9.34 yards is 5 inches: at 4 inches the figures are 7.47 yards exact — order 8, and at 6 inches they are 11.20 yards exact — order 12. The waste behind 9.34 yards is 10%: at 5% the figures are 8.91 yards exact — order 9, and at 15% they are 9.76 yards exact — order 10. A 50-square-foot step moves the exact figure by about 0.85 yard at this depth; a 1-inch step moves it by about 1.87 yards.
What the defaults assume
The defaults assume a flat 550-square-foot mulched area, a uniform 5-inch installed depth, and 10% waste for settling and uneven ground. Real beds slope, have edging that holds shells, and lose material to wind and foot traffic — open, sloped beds deserve more waste, and sheltered beds with edging deserve less. Zero area is the honest edge: 0.00 yards, order 0. Negative area, zero depth, and negative waste are rejected. This chart prices volume only: it does not certify walnut mulch as suited to any plant or soil.
Who uses this
A gardener mulching paths for several seasons: the paths are measured once, the depth is set by the traffic, and the order is the budget line. A landscaper quoting a walnut mulch install: the lookup table prices common sizes on the spot, and the calculator handles the odd shape. A homeowner covering a new border: the border area, not the whole yard, is the area to enter. A groundskeeper topping up paths and beds: the same formula prices the top-up if the area and the missing depth are measured first.
Accuracy & limitations
The arithmetic is exact for the inputs entered; the judgement is in the area and the depth. An area measured at the whole garden instead of the beds overstates the order badly, and an installed depth that later packs down is not the depth plants enjoy. The model does not account for edging, drainage, weed fabric, delivery minimums, or walnut's effect on sensitive plants — confirm the mulch suits the planting before ordering. This page is a calculation tool, not gardening advice.
Cite this calculator
Walnut mulch for 550 sq ft at 5-inch depth with 10% waste: 605.00 sq ft needed, 9.34 cubic yards exact, order 10. Source: Bright Side Kit, https://brightoolbox.com/walnut-mulch-chart/, accessed 29 October 2026 (2026-10-29).
Frequently asked questions
Why does walnut mulch settle after it is laid?
Because shells pack tightly when first spread, then shift under rain and foot traffic, closing the voids between them. A path laid at 5 inches may sit nearer 4.5 inches within weeks, which is why the 10% waste here is a floor and a top-up after the first rain is normal.
Should I measure the whole garden or just the beds and paths?
Just the beds and paths you will cover. Lawn, patios, and bare soil you leave unmulched need no walnut mulch, and measuring them inflates the order by the whole unmulched area.
Why order 10 yards when the exact figure is 9.34?
Because suppliers sell whole yards and the shells settle: the 0.66 yard of rounding is the first top-up. Ordering exactly 9.34 is impossible, and ordering 9 leaves the beds short before settling even starts.
How long does walnut mulch last?
It breaks down very slowly, so depth should be checked each season and topped up to the installed depth. The 10% waste in this chart covers spreading loss on the first install, not years of breakdown — budget top-ups separately.
Is walnut mulch safe for all plants?
No. Walnut shells contain compounds that some plants dislike, so they suit paths and beds of tolerant plants best. For beds of sensitive seedlings, check the planting first; the volume formula is the same either way.
What if my bed is not a rectangle?
Break it into rectangles and add the areas, or measure the longest length times the longest width and accept a small overestimate. For an L-shaped bed, two rectangles are exact; a single bounding rectangle overstates the order, which is safer than understating it.