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YardPlanHQ

How Much Mulch Do I Need?

Most mulch mishaps come from two places: misreading the area, or mixing units mid-sum. This guide gives the arithmetic itself — and the Mulch Calculator does all of it for several beds at once.

Step 1: measure the beds

Rectangle and circle beds are straightforward (see how to measure a garden bed). If a bed is an odd shape, split it into rectangles, circles and triangles and measure each part — the calculator combines the total.

Step 2: choose a depth

Bagged retail mulch usually performs best around 2 to 4 inches: 2 inches is a top-up for last year's layer, 3–4 inches for a fresh bed or weed suppression. Rubber mulch and coarser barks read on the shallower end. Use the depth the job requires, not a reflex 6 inches — deep mulch can starve roots of air. The calculator offers these depths as options, not as rules.

Step 3: run the volume math

For each section, in feet and inches:

Worked example: a 10 ft × 10 ft bed, 3 inches deep = 100 sq ft × 3 ÷ 12 = 25 cubic feet ≈ 0.93 cubic yards.

Step 4: add an allowance, pick the bag size

Set a waste allowance (10 % is sensible) for spillage and settling. Check the actual bag volume on the shelf — 1.5, 2, 2.5 and 3 cubic feet bags are all common, and the count changes with the box. The worked example with 10 % becomes 27.5 cubic feet, which is 14 two-cubic-foot bags. Bulk delivery is usually cheaper above roughly a yard; run both prices in the calculator's comparison.

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