Mulch Calculator for Beds Along a Connecticut Stone Wall
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The mistake this page exists to catch is depth. Someone measures four hundred square feet of foundation bed, reads that three inches is right, and orders three inches on top of the two inches already sitting there from last spring. What goes down is five, the roots underneath spend a wet New England summer short of air, and the following March the whole bed is still sodden when everything around it has drained. A mulch calculator gives you a yardage in seconds. Deciding what depth to feed it takes a minute with a trowel.
Reading what is already on the bed
What we'd check first is the layer you have. Scrape down at the edge of a bed with a trowel until you reach soil, and measure. If there is less than two inches and it is loose, the bed wants topping, not stripping, and two inches over it brings the total where it should be. If it is matted into a crust that sheds water, or gray and fungal underneath, break it up with a rake or take it out before you order.
Bare ground is the simple case and takes three inches.
Measuring beds that curve away from the wall
Foundation beds and the beds that follow an old stone wall are rarely rectangles, but they are close enough to one if you average. Run the tape along the wall for the length, then measure the bed's width at three or four points and take the middle figure. A bed that swells around a shrub and pinches at a downspout still averages out.
Tree rings are honest circles. Measure straight across the ring for the diameter, not from trunk to edge. A six-foot ring is 28.3 square feet of bed, and a pair of them adds up to more than most people guess.
Island beds with a curved nose are two rectangles end to end, or one rectangle at the average width, and either is within a wheelbarrow of the truth.
Entering beds, rings and the strip by the garage
Rectangle for a run of bed, circle for a tree ring using the full diameter across, or the multiple-areas option when you want the whole property in one figure. It holds five areas, which usually covers the front beds, the side strip and a couple of rings before you have to run it twice and add the totals.
Dimensions in feet, depth in inches from 0.25 to 24. Choose the material, since the weight per yard is nothing like stone. There is a 5% box for compaction and spillage; on a bed being topped up by hand it is optional, and on a big spread where a good share of the load ends up on the tarp and the lawn it is worth ticking. Cubic yards, tons and cubic feet come back, and you can email the estimate to yourself.
Depths that keep bark, roots and voles apart
Two inches over loose existing mulch. Three inches on bare ground, which is enough to stop most weed seed germinating and to hold moisture through a dry July. Four inches is the ceiling anywhere in the landscape.
Keep an open ring three to six inches clear around every trunk. Mulch banked against bark keeps it damp, rot follows, and on a rural lot the pile is an invitation to voles over the winter. Low and flat, never mounded up the stem.
Playground surfacing is a separate material and a separate depth. Landscape shred is not certified fall protection, so use a playground-rated chip six inches deep or more if that is the job.
What a spring refresh of a typical front yard comes to
An illustration rather than a customer job. Say the foundation beds run 41 feet by an average of 4 feet and hold a loose inch and a half of last year's mulch, so they get two inches. Two maples have six-foot rings on bare soil at three inches. The depth box takes one figure for a whole run, so that is two passes of the tool added together.
- Beds: 41 x 4 = 164 sq ft; 164 x 2 / 12 = 27.33 cu ft; / 27 = 1.01 cu yd
- Rings: 3.1416 x 3 x 3 = 28.27 sq ft each, x 2 = 56.5 sq ft
- 56.5 x 3 / 12 = 14.14 cu ft; / 27 = 0.52 cu yd
- Total: 1.53 cu yd, which is about 21 bags at 2 cubic feet each
- Weight: 1.53 x 600 lb = roughly 920 lb, or 0.46 tons
Round that to 2 yards and the spare goes on the strip behind the garage that everyone forgets.
Where a pile can sit on an old driveway
Bulk arrives as one heap, so decide where it goes before it comes. Two or three yards takes up about a parking space. Put a tarp down first, because shredded mulch stains new concrete and leaves a dead rectangle on grass if it sits for two weeks. On a narrow drive between stone walls, check the truck can reach the spot and still turn.
Spread it within a week or two. A pile left standing a month heats in the middle and sours, and a soured load has to be turned and aired before it goes near a bed.
Why mulch is the one material you never buy by the ton
Everything else on this site is priced and hauled by weight. Shredded mulch weighs about 600 lb per cubic yard, which is 0.30 tons, so a load fills a truck by volume long before it troubles the axles. That is also why the bag comparison works cleanly: one cubic yard is 27 cubic feet, so it equals 13.5 bags of the 2-cubic-foot size, or 9 of the 3-cubic-foot size.
| Depth | 1 cubic yard covers | 10 bags at 2 cu ft cover |
|---|---|---|
| 1 in | 324 sq ft | 240 sq ft |
| 2 in | 162 sq ft | 120 sq ft |
| 3 in | 108 sq ft | 80 sq ft |
| 4 in | 81 sq ft | 60 sq ft |
Chips, nuggets and dyed shred all use the same volume arithmetic, so the yardage does not change with the type; only the look and how often you top it up.
If the job is filling a bed rather than covering one, you want a different tool. The soil calculator sizes garden soil for raised beds and planting holes, and the topsoil calculator handles lawn and bed prep over rocky ground. When the mulch figure looks right, set the quantity and the delivery date on the product page, where delivery is arranged at checkout by ZIP code.
Common questions
Some beds are bare and some already have mulch. Do I order one depth for everything?
Run them as two calculations and add the yardages. The depth box takes a single figure for every area in a run, so bare beds at three inches go through in one pass and topped beds at two go through in another. It is the same material either way, so nothing has to be kept separate on the drive.
The island bed is a long oval with a curve at each end. What numbers do I use?
Measure the longest line down the middle, then the width at three places and average it. An oval entered as a rectangle at its average width over-orders very slightly, which on mulch is a wheelbarrow rather than a problem.
How do I know how much I need if I am only freshening what is there?
Measure what is missing, not what you want in total. Dig to soil at the edge, see what depth is left, and enter the difference. Beds that held two inches last April are usually down to an inch by the following spring, so a one-inch top-up at 324 square feet per yard goes a surprisingly long way.
I underestimated and ran out with two beds to go. What now?
Spread what you have at the right depth and leave the last beds bare until the next order rather than stretching the pile thin. A half-inch skim does not suppress weeds and does not hold moisture, so it is work done twice.
How exact is the yardage the tool gives back?
The arithmetic is exact for the figures you enter, and the variables are yours: the average width you settled on and how evenly the layer goes down by hand. Ordering the next half yard up absorbs both, and mulch is the one material where a little spare always finds a home.
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