Shredded Mulch in Maryland: Getting the Depth Right Before the Yardage

The mistake shredded mulch usually gets bought to fix is bare soil around foundation plantings, baking and crusting through a humid Maryland August while weeds take the open ground. The mistake it often creates is the fix repeated. Two fresh inches go on every April, on top of last April's, until the layer is six inches deep, water stops reaching the roots and the stems of the shrubs are buried. Depth is the whole discipline of this material, and the number on the spec is not an annual allowance.

The shredded mulch ticket: hardwood shreds, natural brown, 2 to 4 inches

Two things follow from that weight, which comes from this site's own published figures. Mulch is sold and ordered by the cubic yard rather than by the ton, because a yard of it weighs about a fifth of what a yard of stone does. And a load that looks enormous on the drive covers less ground than people expect once it is raked out to depth.

Bed, tree ring, foundation planting or bare slope: depth for each

Keep it on the surface rather than digging it in. It is a cover for soil, not a component of it, and a bed that wants body underneath wants Garden Soil worked in before the mulch goes over the top.

Humid summers, Bay-country downpours and the winter in between

Maryland gives mulch a harder year than the catalogue photograph suggests. Hot, humid summers are exactly when a bed benefits most from being covered, and that is the argument for the material. But the same season delivers thunderstorms that can lift a shallow layer off a slope in ten minutes, and the tropical systems and nor'easters that follow do it on a larger scale. Shredded material holds better than nuggets on a grade because the fibers knit together, which is the main reason it is the format sold for slopes.

Ground matters too. On heavy Piedmont clay that stays wet, a deep layer holds water against the soil surface longer than the plants want, so stay at the lower end of the depth range. On sandier Eastern Shore ground that drains fast, the upper end of the range earns its keep. Through winter the layer moderates the swing around roots as the ground freezes and thaws, and by March it has flattened and darkened, which is decomposition rather than failure. That breakdown is what feeds organic material back into the soil, and it is also why beds want topping rather than rebuilding.

The patio base, the dry creek and the fire pit: three loads to order differently

Three jobs get quoted alongside a mulch order often enough to work through. All are examples rather than real projects, and none of them is mulch.

• Example, a paver patio base 14 feet by 18 feet, or 252 square feet, at 4 inches compacted: 252 x 0.3333 = 84 cubic feet, divided by 27 = 3.11 cubic yards, about 4.7 tons of CR-6 at roughly 1.50 tons per cubic yard. Organic material under pavers decomposes and the patio follows it down.
• Example, a dry creek bed 26 feet long and 3.5 feet wide, or 91 square feet, at 5 inches: 91 x 0.4167 = 37.9 cubic feet, divided by 27 = 1.40 cubic yards, about 1.9 tons of Large River Rock at roughly 1.35 tons per cubic yard. Mulch in a channel floats and ends up in the lawn.
• Example, a fire pit surround, a 12 foot circle with a 4 foot pit in the middle. Circle area is diameter times diameter times 0.7854, so 113.1 square feet less 12.6 square feet leaves 100.5 square feet. At 3 inches: 100.5 x 0.25 = 25.1 cubic feet, 0.93 cubic yards, about 1.3 tons of 3/8" Natural Pea Gravel at 1.40 tons per cubic yard. Nothing combustible belongs in a ring around a fire.

For the mulch itself the arithmetic is the same and the answer stays in yards. A border 60 feet by 4 feet, or 240 square feet, at 3 inches is 240 x 0.25 = 60 cubic feet, divided by 27 = 2.2 cubic yards, which weighs roughly 1,300 lb. Four tree rings at 6 feet across are 4 x 28.3 = 113 square feet, and at 3 inches that is 113 x 0.25 = 28.3 cubic feet, about 1.05 cubic yards. Both together sit a little over 3 yards.

Ordering by the yard, and the hour before the truck arrives

Check your figures in the mulch calculator, then choose a quantity and a delivery date here. Maryland Rock Supply arranges delivery at checkout by ZIP code, and the driver needs clear access to a spot where the load can be tipped.

Before the truck comes, settle four things. Where the pile goes, which wants to be as close to the beds as the truck can safely reach and on a hard surface rather than on grass. What goes under it, because a tarp turns the last wheelbarrow load into something you can use and saves an hour of scraping. Whether the beds are weeded and edged, since spreading over weeds buys you a few weeks and no more. And who is moving it, because mulch is light enough that two people with wheelbarrows and a fork will clear three yards in a morning, which is not true of any stone on this site.