Mulch keeps moisture in, weeds down, and beds looking finished — but only at the right depth. Too little and weeds push through; too much and you can suffocate roots.
How deep should mulch be?
For most beds, 2 to 3 inches is the sweet spot. That's enough to block light to weed seeds and hold soil moisture without smothering plant roots. Around trees, keep mulch a couple of inches away from the trunk — piling it against the bark (a "mulch volcano") traps moisture and invites rot and pests.
How much area does a yard of mulch cover?
Coverage depends entirely on depth. The deeper you spread it, the less area a given amount covers:
| Depth | Coverage per cubic yard |
|---|---|
| 1 inch | ~324 sq ft |
| 2 inches | ~162 sq ft |
| 3 inches | ~108 sq ft |
| 4 inches | ~81 sq ft |
To skip the math, measure your bed's area and desired depth and drop them into our mulch calculator — it tells you how many cubic yards and how many bags to buy.
Bags vs bulk: which is cheaper?
Bagged mulch is convenient for small beds and easy to carry, but it costs more per cubic foot. Bulk mulch delivered by the cubic yard is much cheaper once you need more than about 8 to 10 bags. As a reference, one cubic yard equals 13.5 of the standard 2-cubic-foot bags.
Which mulch should you use?
Shredded hardwood is the all-purpose choice and knits together well on slopes. Bark nuggets last longer but float in heavy rain. Dyed mulches hold color longest. Whichever you choose, the coverage numbers above are the same — the mulch calculator works for any type.
Try the free calculator
Skip the manual math — get instant numbers for your own project:
Frequently Asked Questions
How much mulch do I need?
Measure the bed area and multiply by your depth (usually 2 to 3 inches). One cubic yard covers about 108 square feet at 3 inches deep; a mulch calculator gives your exact amount.
How deep should mulch be?
Two to three inches is ideal for most beds — enough to suppress weeds and hold moisture without smothering roots. Keep it away from tree trunks and plant stems.
How many bags of mulch are in a cubic yard?
One cubic yard equals 13.5 standard 2-cubic-foot bags of mulch, so a yard is far cheaper than buying bags once you need more than about 8 to 10.
How many square feet does a yard of mulch cover?
A cubic yard covers roughly 162 square feet at 2 inches deep or 108 square feet at 3 inches deep. Deeper mulch covers proportionally less area.