Mulch Calculator

Mulch is sold two ways: in bags from box stores and garden centers, or in bulk cubic yards from landscape supply yards. The math to figure out how much you need is the same either way, and it comes down to a simple volume calculation you do in your head at the yard.

Multiply the length of the bed in feet by the width of the bed in feet by the depth of mulch in feet. Depth is nearly always specified in inches, so divide inches by twelve before you multiply. A thirty foot by six foot bed with three inches of mulch is 30 x 6 x 0.25 = 45 cubic feet of mulch, or 45 divided by 27 = 1.67 cubic yards.

In bags, a two cubic foot bag is the standard size at most box stores. Divide total cubic feet by two to get the bag count: 45 cubic feet is 23 bags. Some brands sell three cubic foot bags, which drops the count to 15. For anything larger than about ten bags, bulk mulch from a yard usually beats bagged mulch on delivered cost per cubic yard, sometimes by a factor of two or three.

Depth is not one number. For ornamental beds around shrubs and perennials, two to three inches of mulch is the standard. That is enough to suppress weeds, hold soil moisture, and moderate root temperature without smothering the plants. Any deeper than four inches and you risk creating an anaerobic layer that rots stems and encourages fungal problems.

For a fresh new bed with weed cloth or landscape fabric underneath, three inches is a good starting depth. It will settle to about two inches over a year and give you a full growing season before you need to top off.

For playground surfacing, the standard depth is nine to twelve inches of engineered wood fiber or a certified playground mulch. That is what the ASTM F1292 standard for impact attenuation calls for under swings and slides at fall heights up to about six feet. A twenty by twenty foot play area at twelve inches of depth is 400 cubic feet, or almost fifteen cubic yards. That is a full tandem dump truck load of bulk mulch.

Around trees, a two to four inch ring of mulch out to the drip line is ideal, but keep the mulch pulled back from the trunk itself. The infamous "mulch volcano" piled up against a trunk is a slow way to kill a tree by inviting rot and boring insects into the bark.

Hardwood mulch is the default for ornamental beds because it breaks down slowly, adds organic matter to the soil, and comes in a range of natural and dyed colors. Shredded hardwood, sometimes called triple-shred or double-ground, holds its position on slopes and resists blowing away. Bark nuggets are chunkier, look tidier around trees, and last longer, but they float and wash out of beds during heavy rain.

Cedar mulch has a natural insect deterrent from the oils in the wood and lasts longer than pine or hardwood. It is more expensive per cubic yard but is worth the premium in areas where termites and carpenter ants are a real concern, which is most of Texas.

Pine straw is the cheapest per bed and drains extremely well. It is the standard mulch across the pine belt of East Texas and much of the deep South. It knits together into a mat that resists erosion but breaks down faster than hardwood and needs to be topped up twice a year.

Dyed mulch keeps its color longer than natural mulch, but the dye itself is a marketing decision more than a horticultural one. Any mulch color fades by the second summer. If long-term color matters, plan on a light one-inch top-off every spring rather than a full new install every three years.

Bulk mulch is priced per cubic yard, delivered on a pallet, or dumped loose in the driveway. A typical residential delivery is between three and ten cubic yards. A tandem dump truck can carry up to twelve yards of mulch loose. If you have twenty yards or more, a walking floor trailer or a semi-dump is the efficient way to move the material.

In North and Central Texas, the mulch season starts in late February and runs through May, then picks up again in September for the fall installation season. Prices tend to be lowest in late winter and climb through the spring rush.

For big installations, ask the yard about screened versus unscreened mulch. Screened material has been run through a rotary screen to remove tramp material, sticks, and oversized chunks. Unscreened is cheaper but requires you to rake out the debris as you spread, which eats the savings in labor.

Mulch installs, bed edging, and seasonal cleanups are search-driven work. Homeowners search "landscaper near me" or "mulch installation" in early spring, and whoever ranks first books the season. Peak Local Leads builds and ranks local landscaping sites for one contractor per Texas market. Seven day free trial on the calls, flat monthly after, no per-lead fees. If your area is open, that is the offer.