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How many bags of mulch for this bed?
Measure the bed once, get the volume in the units the store actually sells.
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Garden
How mulch volume is calculated
Bed length × width × depth gives the volume in cubic feet. Dividing by 27 converts to cubic yards, which is how bulk mulch is sold. Dividing by the bag size gives the number of bags.
Why depth is the variable that matters
Two inches suppresses weeds and holds moisture; three inches smothers more but can starve shallow roots. More than four inches often does harm and wastes money. Bag labels quote volume, not coverage, so the depth has to be explicit.
Who it is for
Gardeners buying mulch for beds, borders or around trees, in bags or by the yard.
Frequently asked questions
How deep should mulch be?
Two to three inches for most beds. Keep it a few inches away from trunks and stems, and do not bury low-growing plants.
Bags or bulk?
Bulk is cheaper above roughly one cubic yard, if you can take delivery and move it. Bags make more sense for small beds and for carrying in a car.
Should I remove old mulch?
Usually no. Top up to the target depth. Remove it only if it has matted into a water-repellent layer or is contaminated with weeds.