Every successful landscaping project — from a new lawn to a raised vegetable bed — starts with the right topsoil. But "topsoil" is not a single product. It is a category that covers a wide range of soil types with dramatically different properties. The type you choose determines how well water drains, how deeply roots can grow, and how much you ultimately spend on amendments and replacements.
This guide breaks down the main types of topsoil by texture and composition, explains what each is best used for, and shows you how to use the BuildersMeasures Topsoil Calculator to order the right volume for your specific soil type — including the settling buffer that most people forget.
What Is Topsoil, Really?
Topsoil is the uppermost layer of soil — the A horizon — where organic matter accumulates and where most plant roots do their work. It is darker than the subsoil below it because of decomposed organic material, and that organic content is what gives good topsoil its crumbly structure, water-holding capacity, and nutrient exchange ability.
True topsoil ranges from 2 to 10 inches thick in natural settings, depending on the region and land history. When you buy topsoil from a supplier, you are typically buying a screened and blended material designed to mimic or improve on native topsoil. But the quality varies enormously — and the type you get matters more than the brand name.
The Four Texture Classes You Need to Know
Soil texture is determined by the proportions of sand, silt, and clay particles it contains. These proportions determine almost everything about how the soil behaves: how fast it drains, how much water it holds, how easy it is to dig, and how well roots can penetrate. There are four broad texture classes that matter for topsoil selection.
1. Sandy Topsoil
Texture: Gritty when rubbed between fingers. Over 70% sand particles.
Drainage: Excellent. Water moves through quickly and does not pool.
Water and nutrient retention: Low. Sandy topsoil dries out fast and leaches nutrients, especially nitrogen and potassium.
Best uses: Improving drainage in heavy clay soils, filling deep planting holes for drought-tolerant plants, and as a base layer under sandboxes or play areas. Sandy topsoil is also useful for cacti and succulents that rot in moisture-retentive soil.
Limitations: Sandy topsoil alone is a poor growing medium for most vegetables and lawn grasses. It needs compost or organic matter mixed in to hold water and nutrients. When using the Topsoil Calculator, remember that sandy topsoil settles less than loamy soil — a 10% settling buffer is usually sufficient.
2. Clay Topsoil
Texture: Sticky when wet, hard and cloddy when dry. Over 40% clay particles.
Drainage: Poor. Water sits on the surface and drains slowly, which can drown roots and cause rot.
Water and nutrient retention: Very high. Clay particles hold onto water and nutrients tightly, but they also hold onto them too tightly for some plants to access.
Best uses: Clay topsoil is rarely sold as a standalone topsoil product. It is more commonly encountered when the native soil on a site is clay-heavy. In that case, the clay must be amended with compost or sand before it can support most landscape plants.
Limitations: Clay compacts easily, especially under foot traffic or machinery. Compacted clay cannot drain, and roots struggle to penetrate it. If you are spreading topsoil over existing clay, you need a deeper layer — at least 6 to 8 inches — so roots have room to establish before hitting the clay layer. The settling buffer for clay is also higher, typically 18–20%.
3. Silt Topsoil
Texture: Smooth and floury when dry, slippery when wet. Silt particles are between sand and clay in size.
Drainage: Moderate. Better than clay, but silt can still form a crust when dry that slows water infiltration.
Water and nutrient retention: Good. Silt loam is one of the best natural soil textures for plant growth because it holds moisture without becoming waterlogged.
Best uses: Silt loam is an excellent topsoil for lawns, flower beds, and vegetable gardens. It is easy to work, drains adequately, and holds nutrients well. If you find a supplier selling "silt loam" or "loam" topsoil, that is usually the premium product you want.
Limitations: Pure silt topsoil (without enough sand or clay to balance it) can crust over after rain, which slows water absorption and makes it hard for seedlings to emerge. It is also easily eroded by wind and water. Blend it with compost to improve structure.
4. Loam Topsoil — The Gold Standard
Texture: Crumbly, soft, and slightly moist when squeezed. Loam is a balanced blend of roughly 40% sand, 40% silt, and 20% clay.
Drainage: Good. Loam drains well but still holds enough moisture for plants to thrive.
Water and nutrient retention: Excellent. Loam has the best balance of water-holding capacity and aeration. It is fertile, easy to work, and does not compact easily.
Best uses: Loam is the ideal topsoil for almost every landscape application. New lawns, flower beds, vegetable gardens, shrub borders, tree planting — loam handles all of them well. The Utah State University Extension calls loam and silt loam the "ideal soil texture" for landscape plants.
Limitations: True loam is not always available in bulk, and suppliers may sell lower-grade blends as "loam" when they are not. Ask for a soil test showing the sand, silt, and clay percentages. Loam is also the densest topsoil type, so it weighs more per cubic yard than sandy or silty topsoil — about 2,600 to 2,800 pounds per yard. The Topsoil Calculator automatically estimates weight based on your selected soil type, so you can confirm truck capacity before ordering.
Topsoil Grades: What Suppliers Actually Sell
Beyond the texture classification, topsoil is also sold in grades that reflect how much processing it has undergone. The Royal Horticultural Society in the UK identifies three broad grades that apply in most markets:
Premium grade: Screened to a fine particle size, high in fertility, loamy in texture, and free from weed seeds and contaminants. This is the topsoil you want for flower borders, raised beds, and any project where quality matters most. It is also the most expensive.
General-purpose grade: Also good for beds, borders, and lawns, but may have larger screen sizes and slightly less fertility than premium. Coarser grades are especially useful for turf laying, while finer grades work well for top dressing lawns.
Economy grade: Supplied "as dug" — meaning unscreened and unblended. It is used where volume matters more than quality, such as building up grade on a large site. Economy topsoil often contains stones, roots, and weed seeds.
When ordering bulk topsoil, always ask which grade the supplier is quoting. The price difference is significant, and the quality difference is even larger.
How to Choose the Right Topsoil for Your Project
The right topsoil depends on three things: what you are growing, what is underneath, and how much you want to spend. Here is a quick decision framework.
For a new lawn from seed: Loam or silt loam, 4 to 6 inches deep. If the existing subsoil is clay, go to 6 inches. Use the calculator's "New lawn from seed" preset to set the depth automatically.
For a vegetable garden: Loam, 8 to 12 inches deep. For raised beds, 12 to 18 inches. Blend 70% topsoil with 30% compost. The calculator's soil mix blender splits the volume into topsoil and compost automatically.
For flower beds and borders: Loam or silt loam, 6 to 8 inches. Premium grade is worth the extra cost here because weed seeds in economy topsoil will keep coming back for years.
For filling low spots in a lawn: Screened loam or sandy loam, applied at 0.5 to 1 inch. Use fine-grade topsoil so it blends into the existing grass.
For drainage improvement: Sandy topsoil, blended with existing soil at a 50/50 ratio. Do not use clay or heavy loam for drainage work.
Why the Type of Topsoil Changes How Much You Need
Different topsoil types settle differently. Sandy topsoil settles about 10% after spreading and watering. Loam settles 15%. Clay and compost-heavy blends settle 18 to 20%. If you order the raw calculated volume without adding a settling buffer, you will end up short — every time.
The BuildersMeasures Topsoil Calculator solves this by including a visible settling buffer selector. Choose 10% for sandy soil, 15% for standard loam, or 18–20% for raised beds and compost-rich blends. The calculator adds the buffer to your raw volume and gives you the order quantity that actually delivers the depth you planned.
It also handles multi-zone planning — so if you are ordering topsoil for a front lawn, a side bed, and a raised vegetable bed at the same time, you can enter each zone separately and the calculator will sum the total volume, weight, and cost. No more guessing how much to add on top for the second bed.
Testing Topsoil Quality Before You Buy
Before committing to a bulk order, ask the supplier for a recent soil test. ASTM D5268-23 — the Standard Specification for Topsoil Used for Landscaping and Construction Purposes — defines the properties that matter: organic matter content, pH, salt content, and texture. A supplier who cannot provide these numbers is selling unknown quality.
Three quick field tests you can do yourself:
The squeeze test: Moisten a handful of soil and squeeze it. Loam crumbles with a light touch. Clay forms a sticky ribbon. Sand falls apart immediately.
The jar test: Fill a jar one-third with soil, top it with water, shake it hard, and let it settle. Sand settles first (bottom layer), silt next (middle), and clay last (top). The proportions tell you the texture class.
The smell test: Good topsoil smells earthy and fresh. Sour or chemical smells indicate poor aeration or contamination.
For any order over 5 cubic yards, it is worth paying for a professional soil test. The cost — usually $20 to $50 — is a fraction of what you will spend replacing plants that fail in poor soil.
The Bottom Line
Topsoil is not a commodity. Sandy topsoil, clay topsoil, silt loam, and true loam behave in completely different ways, and choosing the wrong one for your project means wasted money and struggling plants. Know your texture class, know your grade, and know your settling buffer. Then use the Topsoil Calculator to turn those decisions into a precise order volume — one that accounts for settling, multi-zone layouts, and the real density of the soil you are buying.
Whether you are covering 200 square feet of raised beds or 2,000 square feet of new lawn, the right topsoil type and the right order quantity are the two decisions that determine whether the project thrives or fails.