How to calculate a flower bed mulch
A fresh layer of mulch is the quickest way to tidy a bed, and measuring it takes only a minute.
- Measure each bed, or split a curved bed into simple shapes.
- Choose a depth, commonly 2 to 3 inches.
- Add the totals and order about 10 percent extra.
- Spread evenly and keep mulch off plant stems.
Worked example
For a typical flower bed mulch with length 20 ft, width 4 ft, depth 3 in, the volume is 20.00 cubic feet. Divide by 27 for 0.74 cubic yards. With a 10 percent allowance, plan for 0.81 cubic yards.
In mulch, 0.74 cubic yards weighs about 0.26 US tons at a planning value of 700 pounds per cubic yard.
Flower Bed Mulch sizes and quantities
These common sizes are calculated with the same formula as the tool above, so you can find your number quickly.
| Size | Cubic feet | Cubic yards | With 10 percent extra | US tons |
|---|---|---|---|---|
| 10 by 3 ft, 2 in | 5.00 | 0.19 | 0.20 | 0.06 |
| 20 by 4 ft, 3 in | 20.00 | 0.74 | 0.81 | 0.26 |
| 40 by 6 ft, 3 in | 60.00 | 2.22 | 2.44 | 0.78 |
| 60 by 8 ft, 4 in | 160.00 | 5.93 | 6.52 | 2.07 |
Tips
- Bulk delivery saves money over bags.
- Dark, double shredded mulch holds its color longer.
- Edge the bed first so the mulch stays in place.
Common mistakes to avoid
- Piling mulch against tree trunks.
- Applying 6 inches, which can suffocate roots.
- Measuring only the long side of a curved bed.
These figures are planning estimates. Real material varies in moisture, size, and compaction, so confirm weights and order quantities with your supplier.
Frequently asked questions
How many cubic yards do I need for a flower bed mulch?
Multiply the dimensions in feet and divide by 27. The example above, length 20 ft, width 4 ft, depth 3 in, needs 0.74 cubic yards before waste.
How much extra should I order?
Add 5 to 10 percent for waste. Add more if the ground is uneven or the material is loose.
Can I enter inches and feet together?
Yes. Each box has its own unit selector, so you can mix feet and inches.
How much does flower bed mulch material weigh?
0.74 cubic yards of mulch weighs about 0.26 US tons as a planning value.