Mulch, Gravel, Topsoil & Sand: What to Buy and How Much You Need

What type of mulch should I use?

For most planted beds, shredded bark or wood chips. Minnesota Extension rates wood chips and shredded bark as suitable for trees, shrubs and perennial beds because they last and break down slowly¹. Organic mulch earns its place four ways: it reduces evaporation and helps soil hold water, it blocks the light weed seeds need to emerge, it insulates the surface against temperature swings, and it adds organic matter as it decomposes¹. Because it decomposes, it needs refreshing every few years³.

Stone mulch is the durable alternative for areas without plants. It lasts, but it doesn’t improve the soil, may raise soil temperature¹, and rock gets hot enough in summer to stress sensitive plants³. Don’t pick a mulch by colour alone: particle size, source, how fast it breaks down and whether it suits the plants matter more.

How deep should mulch be?

Two to four inches for most garden and landscape beds. Minnesota puts the range at 2 to 4 inches to balance weed suppression with soil aeration¹; Penn State says 2 to 4 inches “and no more,” less on poorly drained soil, and only 1 to 2 inches of fine or double-shredded mulch, which lets less oxygen through to the roots⁵. Illinois matches it: 2 to 4 inches, composted materials at the low end and coarse mulches at the high end⁴.

Keep it off trunks and stems. Minnesota asks for a 6-inch mulch-free ring around tree trunks and clear space at plant stems to prevent rot and pests¹, and pulls mulch at least 4 inches back from a newly planted tree². Mulch heaped against the trunk, the “volcano,” is never recommended; it holds moisture on the bark and favours carpenter ants, termites and disease⁵⁶.

When topping up an existing bed, measure what’s there first. Illinois says to check the depth and rake matted layers rather than piling on more⁴; you may only need a thin top-up, not another full layer.

Should I put landscape fabric under mulch?

Not in an ordinary planted bed. Minnesota’s guidance separates the two barriers: landscape fabric is generally permeable, while landscape plastic blocks unwanted growth but causes problems with dry or wet soil, so plastic belongs on pathways and areas that aren’t supporting plants³. In a bed, removing existing weeds and keeping the mulch at the right depth does the weed control, and the mulch can feed the soil as it breaks down instead of sitting on a sheet.

What’s the difference between crushed stone and pea gravel?

Particle shape. Crushed stone is angular; when graded and compacted, the edges catch on each other and the layer packs to a nearly solid surface that suits paths and patios with foot traffic. Pea gravel and other river-run gravel is rounded and never packs down; the pieces slip and slide underfoot, which makes it better as a ground cover than as a walking surface⁷. For a compacted path, choose crushed angular material; for a decorative border or informal garden area, pea gravel is fine.

What gravel should I use for a driveway?

A driveway needs more than a decorative top layer. Its performance depends on the soil underneath, drainage, the traffic it carries and properly compacted aggregate layers. Suppliers sell graded crushed aggregate for driveways, a mix of particle sizes and fines that compacts into a firm surface; ask for that product by name rather than assuming decorative stone or loose pea gravel will behave the same way. The base thickness is site-specific: vehicle loads, soil, frost and drainage all change it, so confirm it with the supplier or installer before ordering.

How deep should a gravel walkway be?

It depends on whether you want a decorative surface or a structural path. For a garden path, University of California Master Gardeners give two inches as a practical minimum, and about four inches if thick stones or pavers are set into it⁷. A path that carries wheelbarrows, has to resist rutting or sits on soft soil needs excavation, a compacted base and edging; paver patios, for comparison, sit on 4 to 6 inches of compacted crushed rock⁸. Estimate each layer separately: a base and a decorative top layer are different products at different depths.

Do I need landscape fabric under gravel?

Sometimes. A geotextile can keep soil and aggregate from mixing in some installations, but it doesn’t replace drainage or a properly prepared base, and whether it helps depends on the soil, the load and the design. Ask the aggregate supplier or installer whether a separation layer is appropriate for your path or drive.

What’s the difference between topsoil and fill dirt?

Topsoil is the surface soil that holds most of the organic matter and biological activity; good topsoil, properly selected and prepared, supports lawns and planting areas. Fill dirt is for filling and grading, not for growing: its composition varies and it may be largely subsoil. If you’re establishing a lawn or planting, don’t substitute unspecified fill dirt for topsoil because it’s cheaper.

Is screened topsoil better?

Screening removes larger stones, roots and debris and makes the soil easier to spread. It’s a physical process, not a quality grade: screened topsoil can still be very sandy or clayey, weedy or low in organic matter. Ask about the soil’s origin and composition, whether it has been tested, and whether compost has been blended in.

How can I recognize good bulk topsoil?

Look at it before it’s delivered. Maryland Extension, which notes that topsoil sales aren’t regulated in its state, says to buy from a reputable nursery or dealer, request soil test results and ask about the soil’s origin and how it’s mixed and stored⁹. Its inspection checklist: dark and crumbly with an earthy smell; avoid soil that is very high in sand or clay, foul-smelling, or has grayish mottling or a chalky, sticky or rough texture⁹.

A basic soil test reports pH and buffer pH, phosphorus, potassium, magnesium, calcium and organic matter, with lime and fertilizer recommendations¹⁰. It doesn’t cover contaminants unless you ask: if you’ll grow food, have the lab test for lead as well⁹.

How much topsoil do I need for a lawn?

The job decides the depth. Top-dressing an existing lawn is a thin layer; repairing a low spot takes the measured depth of the depression; establishing a new lawn needs a minimum of 4 to 6 inches of good-quality topsoil, as a firmed or settled depth, per Penn State Extension¹¹. Delivered loose volume settles into a smaller finished volume, so the depth you spread and the depth you end up with differ; the FHWA table shows how large that gap can be, with topsoil at 1,620 pounds per loose cubic yard against 2,430 in place¹⁴.

Can I use topsoil in a raised bed?

Yes, as part of a blend. Maryland’s raised-bed mixes combine topsoil with compost at 1:2 or 1:1, and limit topsoil to 20% of the mix in beds that sit on a hard surface⁹. For ratios, bed depth and what goes underneath, see How to Fill a Raised Garden Bed.

Are all types of sand interchangeable?

No. Sand varies by particle size, shape, grading, cleanliness and intended use, and the names vary between suppliers. Use the material specified for the application.

Can I use ordinary sand under pavers?

Not automatically. A paver installation is a compacted aggregate base of 4 to 6 inches, a 1-inch sand bedding layer and the pavers themselves⁸; bedding sand and jointing material do different jobs. Follow the paver manufacturer’s instructions for material gradation and bedding thickness, and don’t make the sand layer thicker to make up for a thin base.

Will adding sand improve clay soil drainage?

Not in the amounts most people would add. Penn State says clay soils need about 60 percent coarse, uniform sand by volume before drainage improves significantly, which is usually too expensive to be practical¹¹, and its gardening myths page files “add sand to loosen heavy clay” under fiction: clay and sand with rainwater set into a rock-hard, concrete-like mass¹². Dig in organic matter instead, and treat drainage as a grading and soil-structure problem.

What’s the difference between a cubic yard and a ton?

A cubic yard is volume, 27 cubic feet¹³. A ton is weight, 2,000 pounds. A cubic yard of mulch, gravel, topsoil and sand each weigh very different amounts, and even within one material the weight moves with moisture, particle size and density: the FHWA unit-weight table lists dry gravel near 2,730 pounds per loose cubic yard, dry sand near 2,590 and topsoil near 1,620, with wet gravel and sand 20 to 25 percent heavier¹⁴. That spread is why a supplier’s own figure beats any universal conversion chart. The calculator estimates weight for gravel, topsoil and sand from those published densities and lets you type in your supplier’s number instead.

Is it cheaper to buy bulk materials or bags?

Bulk is cheaper per unit, but the delivered price is what you pay. Compare the material price, the delivery fee, any minimum order, the bag count and bag price, whether you have to haul and unload bags, and the leftovers you won’t use.

A hypothetical comparison: you need 1.5 cubic yards of mulch, which is 40.5 cubic feet. At 2 cubic feet per bag that is 21 whole bags; at $4.50 a bag, $94.50 before tax. Bulk at $45.00 per cubic yard plus a $55.00 delivery is $122.50, if the supplier takes an order that small. Bags win here on price alone; on a bigger job the delivery fee spreads over more material and bulk pulls ahead. These prices are illustrative, not quotes.

Enter the prices you’ve been quoted into the calculator’s cost comparison and it will show which comes out lower for your quantities, delivery included.

Should I order extra material?

Sometimes, but no single percentage fits every job. Uneven ground, cutting, handling losses, compaction and settling all change what you need. The calculator deliberately returns the geometric quantity without a waste or compaction allowance; for a structural gravel base, ask the supplier whether the depth you enter should represent loose or compacted material. Gravel compacts by roughly a fifth from loose to in place in the FHWA table¹⁴.

What should I prepare before a bulk delivery?

Choose the drop spot before the truck is booked, and confirm it works:

• The truck can reach the driveway or unloading area.
• Overhead wires, branches and gates are clear.
• The surface can take the delivery vehicle.
• The pile won’t block a sidewalk, road, drain or required access.
• You have permission if material will sit in public space.
• You have a way to move it from the pile to the project.

Ask the supplier whether the quote is a dumped load, a palletized bag delivery or something else.

What mistakes should I avoid?

• Buying the wrong grade. Decorative gravel isn’t a driveway base.
• Ignoring the existing surface. Drainage, weeds, soft soil and grading don’t disappear under a new layer.
• Over-mulching. Deep mulch and material piled against trunks damages plants⁵⁶.
• Buying poor topsoil. Screened doesn’t mean good; inspect it⁹.
• Using the wrong sand. Bedding, mortar, concrete and jointing sands have different specifications.
• Confusing tons and yards. Confirm whether the quote is by weight or volume.
• Ordering before checking delivery conditions. A cheap load becomes expensive when the truck can’t unload safely.