How to Calculate Mulch Needed
Cubic Yards = (Length × Width × Depth in inches ÷ 12) ÷ 27
This converts your area and desired depth into the cubic yard measurement that bulk mulch is typically sold in.
How Deep Should Mulch Be?
Most garden beds need 2-3 inches of mulch. Less than 2 inches doesn't effectively suppress weeds or retain moisture. More than 4 inches can suffocate plant roots and trap excess moisture against stems, leading to rot.
Frequently Asked Questions
At a standard 3-inch depth, 100 square feet requires about 0.93 cubic yards, or approximately 12-13 bags of standard 2-cubic-foot bagged mulch.
Most garden beds need 2-3 inches of depth. Less doesn't effectively suppress weeds; more than 4 inches can suffocate roots and trap excess moisture.
Bulk mulch is almost always cheaper per cubic yard for larger projects (typically 0.5+ cubic yards), while bagged mulch offers convenience for small areas without delivery minimums.