Mulch is sold by the cubic yard, beds are measured in square feet, and most people end up either three wheelbarrows short or with a pile left on the driveway. Here is how to get it right.
How deep should mulch be?
Aim for two to three inches. That is enough to hold moisture and slow weeds without smothering roots.
- Less than two inches and sunlight reaches the soil, so weeds come right through.
- More than three inches in total, old mulch included, and water has trouble getting down, roots can suffocate, and the mulch stays soggy against stems and trunks.
If your beds already have a couple of inches of old mulch, you do not need another three on top. A one inch top-dressing freshens the color and keeps the total where it should be.
The quick math
One cubic yard of mulch covers:
| Depth | Coverage per cubic yard |
|---|---|
| 1 inch | about 324 sq ft |
| 2 inches | about 162 sq ft |
| 3 inches | about 108 sq ft |
So the formula is simple. Measure the length and width of each bed in feet, multiply them to get square feet, add all your beds together, and then:
- For 2 inches: divide total square feet by 162
- For 3 inches: divide total square feet by 108
Example: A front foundation bed 40 feet long and 6 feet deep is 240 square feet. Two island beds add another 150. That is 390 square feet. At three inches, 390 divided by 108 is about 3.6 cubic yards, so you would order 4.
Curved beds are harder to measure. Break them into rough rectangles and round up a little.
Mistakes we see all the time
Mulch volcanoes. Piling mulch up against a tree trunk holds moisture on the bark, invites rot and pests, and encourages roots to circle the trunk. Keep mulch three to five inches back from shrubs and young trees and eight to twelve inches back from mature trunks, so the root flare stays visible.
Mulching over weeds. Mulch slows new weeds. It does not kill established ones. Pull or treat them first.
Skipping the edge. A clean cut edge between lawn and bed is what makes mulch look finished, and it keeps the mulch from washing onto the grass.
Piling it against the house. Keep mulch a few inches below siding and away from the foundation.
Which mulch should you choose?
- Dyed black or brown holds its color for about a season and gives a crisp, uniform look.
- Natural hardwood fades to gray sooner but breaks down into good organic matter for the soil.
For most New Jersey foundation beds, any of these works well. The right depth and a clean edge matter more than the color.
When is the best time?
Mid-spring is the most popular, right after beds are cleaned up and before the summer heat. Fall is also a good time, since a fresh layer insulates roots through winter.
If you would rather skip the measuring, hauling and spreading, our mulching service includes bed cleanup, edging and installation.