One yard of mulch covers 324 square feet at 1 inch deep, 162 square feet at 2 inches deep, or 108 square feet at 3 inches deep

A cubic yard is a fixed volume — 27 cubic feet of material. How much ground it covers depends entirely on how thick you spread it. The standard depth for mulch around plants and trees is 2 to 3 inches. At 2 inches, one yard covers roughly 162 square feet. At 3 inches, it covers roughly 108 square feet. If you spread it thinner at 1 inch, one yard stretches to about 324 square feet, but that depth often isn't thick enough to suppress weeds or retain moisture effectively.

The math is straightforward: divide 324 (the number of square inches in a cubic yard when spread 1 inch deep) by your desired depth in inches. A 2-inch depth means 324 ÷ 2 = 162 square feet. A 3-inch depth means 324 ÷ 3 = 108 square feet. Most landscapers recommend 2 to 3 inches as the sweet spot — deep enough to block sunlight from weed seeds and hold moisture, but not so deep that it traps moisture against the soil and causes rot.

Key Takeaways

  • One cubic yard of mulch covers 162 square feet at 2 inches deep, which is the most common depth for landscaping beds.
  • The same yard covers 108 square feet at 3 inches deep, the maximum recommended depth to avoid moisture and pest problems.
  • Spreading mulch thinner than 2 inches usually fails to suppress weeds or retain soil moisture effectively.
  • Measure your bed in square feet, decide your target depth, and divide 324 by that depth to find how many yards you need.

How to measure your bed and calculate yards needed

Start by measuring the length and width of each bed in feet. Multiply length by width to get square footage. If your bed is irregular, break it into rectangles, calculate each one, and add them together. For example, an L-shaped bed might be a 10-foot by 4-foot rectangle (40 square feet) plus a 6-foot by 3-foot rectangle (18 square feet), totaling 58 square feet.

Once you have your total square footage, decide on depth. If you want 2 inches, divide your square footage by 162. If you want 3 inches, divide by 108. Round up to the nearest half-yard, because partial yards are usually sold as full units and you want enough to finish the job. A 200-square-foot bed at 2 inches deep needs 200 ÷ 162 = 1.23 yards, so order 1.5 yards to be safe.

If you are working with an odd depth — say, 1.5 inches — use this formula: square footage ÷ (324 ÷ desired depth in inches) = yards needed. At 1.5 inches, that's 324 ÷ 1.5 = 216 square feet per yard, so a 200-square-foot bed needs 200 ÷ 216 = 0.93 yards, or 1 full yard.

Why depth matters more than you might think

Mulch at 1 inch deep looks thin and often blows away or settles quickly. Weed seeds still receive enough light to germinate, and the soil underneath dries out faster because the insulating layer is too shallow. Most weeds will push through 1-inch mulch within weeks, especially in spring and summer.

Two inches is the industry standard for good reason. It blocks enough light to prevent most weed seeds from sprouting, holds soil moisture longer, and moderates soil temperature. It also looks intentional and finished in a landscape bed. At this depth, you'll see real results in weed suppression and water retention.

Three inches is the maximum recommended depth. Beyond that, mulch can trap moisture against the soil surface and against tree trunks, creating conditions for rot, fungal growth, and pest problems. Thick mulch also insulates the soil so much that it stays cold longer in spring, delaying plant growth. If you're mulching around a tree trunk, keep mulch 6 inches away from the bark and never pile it higher than 2 inches at the base.

Different mulch types and how they settle

Hardwood mulch, the most common type sold by the yard, is denser than softwood and settles less over time. A 2-inch process of hardwood mulch will still be roughly 1.5 to 1.75 inches after one season. Softwood mulch, which includes pine and fir, breaks down faster and settles more — expect a 2-inch layer to compress to 1 to 1.5 inches by midsummer.

Shredded bark mulch falls somewhere between the two. It's lighter and fluffier than hardwood, so it covers more ground when first spread, but it also settles and decomposes faster. Dyed mulch (usually black or red) is often hardwood that's been treated, and it holds its color and structure longer than natural mulch, so it settles less.

If you're using softwood or shredded bark, order slightly more than your calculation suggests — add 10 to 15 percent extra to account for settling. Hardwood mulch requires less padding, but adding 5 to 10 percent extra is still smart insurance against running short.

Mulch coverage in real-world conditions

The 324-square-feet-per-yard figure assumes level ground and even spreading. In practice, several factors change the outcome. Sloped beds use more mulch because the same volume spread across an incline covers less horizontal ground. A bed on a 20-degree slope might use 10 to 15 percent more mulch than a flat bed of the same square footage.

Existing plants and obstacles also reduce coverage. If your bed is full of shrubs, perennials, or rocks, you're not actually mulching the full square footage — you're mulching around them. Measure the area you're actually going to cover with mulch, not the total bed size. A 100-square-foot bed with a 20-square-foot shrub in the middle means you're really covering 80 square feet.

Compacted soil or clay also affects how mulch settles. Mulch spreads more easily and sits higher on loose, amended soil than on hard-packed ground. If your beds haven't been worked in a while, loosen the top inch or two before spreading mulch — it will cover better and perform better.

Ordering and delivery considerations

Most landscape suppliers and garden centers sell mulch by the cubic yard. Bulk mulch is usually cheaper per yard than bagged mulch, but you need a way to move it — either a truck or a delivery fee. Bagged mulch costs more but is easier to transport and store. A cubic yard of loose mulch is roughly equivalent to 13 to 15 bags of 2-cubic-foot mulch, depending on how densely it's packed.

If you're ordering bulk delivery, ask the supplier about their minimum order. Many require a minimum of 2 to 3 yards. Delivery fees vary widely — some suppliers include delivery in the price for orders over a certain size, while others charge a flat fee or a per-yard fee. Get a quote before ordering.

Mulch is heavy — a cubic yard of wet hardwood mulch weighs 400 to 600 pounds. If you're having it delivered, make sure the delivery truck can access your beds. A standard dump truck needs a driveway wide enough and strong enough to support its weight. If your property has a narrow gate or soft ground, ask the supplier whether they can deliver to the street and whether you can handle moving it yourself.

Common mistakes that waste mulch or leave beds under-covered

The most common mistake is ordering based on bed size without accounting for existing plants. A 10-foot by 10-foot bed looks like 100 square feet, but if it's planted with three shrubs and a small tree, you might only be covering 70 square feet of actual soil. Measure the open ground, not the total bed.

Another mistake is spreading mulch too thin to save money. A 1-inch layer looks like you've done something, but it won't suppress weeds or retain moisture. You'll end up buying more mulch next year to top it off, and you'll still have weed problems in the meantime. Spend the extra money upfront for 2 to 3 inches and you won't need to reapply as often.

Underestimating settling is also common. If you order exactly what your calculation says you need, you'll run short after the mulch compacts. Always round up to the nearest half-yard. It's better to have a small pile left over than to run out halfway through the job.

Frequently Asked Questions

How many bags of mulch equal one cubic yard?

One cubic yard is roughly equivalent to 13 to 15 bags of 2-cubic-foot mulch, depending on how tightly the mulch is packed. A 3-cubic-foot bag is less common, but one yard would equal about 9 of those. Check the bag label for the exact cubic footage and do the math: 27 cubic feet ÷ bag size = number of bags.

Do I need to remove old mulch before spreading new mulch?

No, you can spread new mulch over old mulch if the old layer is still in decent shape and not matted down. If the old mulch is compacted, moldy, or more than 4 inches deep, rake it out or break it up first. Spreading new mulch over a solid mat of old mulch prevents water from reaching the soil.

Can I use less mulch if I use landscape fabric underneath?

Landscape fabric helps suppress weeds, but it doesn't replace mulch depth. You still need 2 to 3 inches of mulch for moisture retention and temperature control. Fabric alone won't hold moisture or moderate soil temperature the way mulch does. Use both for the best results, but don't skip the mulch to save money.

What's the difference between mulch coverage and mulch depth?

Coverage is the ground area the mulch reaches — measured in square feet. Depth is how thick the layer is — measured in inches. One yard of mulch covers 162 square feet at 2 inches deep, but that same yard covers 324 square feet at 1 inch deep. You choose the depth based on your weed and moisture needs, and that depth determines the coverage.

Should I mulch right up against tree trunks?

No. Keep mulch 6 inches away from tree trunks and never pile it higher than 2 inches at the base. Mulch against bark traps moisture and creates conditions for rot, fungal disease, and pest damage. The tree's root flare — where the trunk widens at the base — needs air circulation. Mulch the area around the tree, but leave the trunk itself clear.