Choose the Right Soil for the Base, the Grade, and the Growing Layer

Tony Marsh Aug 28, 2026 · 24 min read

Fill dirt and topsoil may arrive in similar-looking piles, but they perform different jobs. Suitable fill adds volume, builds elevation, and establishes rough grade. Topsoil provides the surface growing layer for grass and other plants.

Many projects need both. A deep lawn depression may need suitable fill through most of its depth and planting-quality topsoil at the surface. A garden may need planting soil but no fill. A driveway may require specified aggregate rather than either product.

The important word is suitable. Labels such as “fill dirt,” “clean fill,” “screened topsoil,” and “garden soil” do not by themselves establish composition, cleanliness, drainage, fertility, compaction performance, or load-bearing capacity. Choose material by function, inspect what is delivered, and defer to project-specific requirements whenever the work must support a load, retain soil, or manage significant drainage.

The short answer: choose by function, not appearance

Use fill dirt when the primary objective is to:

Add substantial bulk volume
Raise an area
Fill a deep excavation or depression
Establish rough grade
Backfill a space, subject to that application’s requirements

Use topsoil or planting soil when the finished surface must support:

Seed or sod
Garden plants
Flowers and ground cover
Shrubs or other landscape vegetation

For deep planted areas, the usual approach is not to fill the entire depth with premium topsoil. Suitable fill creates most of the elevation, and an appropriate growing layer finishes the surface. This separates the volume-building function from the root-zone function.

That principle does not make ordinary fill dirt a universal structural base. Under a building, slab, roadway, retaining structure, or heavily loaded hardscape, the governing design or specification determines what belongs below the finished work. Commercial soil guidance distinguishes ordinary fill from engineered material placed and verified against defined project requirements (Soil Depot’s fill dirt and topsoil guide).

Project	Usual material approach	Reason	Main caution
Deep yard depression	Suitable fill below, topsoil above if planted	Fill supplies economical volume; topsoil creates the growing surface	Diagnose the cause and account for settlement and drainage
Shallow lawn repair	Gradual topdressing or compatible surface soil	Repairs the surface without unnecessarily burying established turf	Keep living grass exposed rather than covering it heavily at once
New lawn	Correct subgrade and elevation first, then install suitable topsoil	The lawn needs both a workable grade and a viable root zone	Growing-layer needs depend on native soil and turf requirements
Vegetable or flower garden	Inspected or tested planting soil, amended as indicated by a soil test	Plants need a suitable root environment rather than plain mineral fill	“Topsoil” does not guarantee fertility, texture, or cleanliness
Landscape berm	Stable fill core with planting soil on rooted surfaces	The core creates shape; the outer layer supports vegetation	Consider drainage, erosion, side slopes, and settlement
General backfill	Material specified for the excavation and its function	Different backfills perform different drainage and compaction duties	Utility, foundation, septic, and wall backfill are not interchangeable
Patio	Specified compacted base, often aggregate rather than generic soil	Hardscape requires resistance to movement and settlement	Remove or retain existing soil according to the design, not a retail label
Driveway	Designed subgrade and specified aggregate or fill system	Vehicle loads and water require controlled support	Landscaping fill may not meet gradation or compaction requirements
Shed pad	Base selected for the shed and foundation design	The pad must support loads and manage water	“Compactable” is a product description, not a structural design
Slab	Material and preparation required by the plans or site design	Slabs are sensitive to uneven support and settlement	Do not substitute ordinary fill without project-specific approval
Retaining structure	Specified structural and drainage materials	Retained soil and water impose demands on the assembly	Follow the wall design rather than choosing by price alone
Wet or high-traffic area	Often specified aggregate or drainage material	Fine soil may rut, hold water, or become difficult to compact	Diagnose the water source and drainage path before adding material

Drainage, native soil, expected loads, vegetation, climate, access, and local requirements can override any recommendation based only on a product name. “Fill below, topsoil above” is a useful landscaping principle, not a substitute for site design.

What fill dirt and topsoil actually contain

Fill dirt is generally low-organic mineral soil, often sourced from subsoil or excavation. Depending on local geology and the source, it may contain varying proportions of clay, sand, silt, gravel, and small rocks. One load may be relatively uniform; another may contain noticeably different pockets of material.

Low organic content is useful when the objective is to build volume without relying on material that can lose volume as organic matter decomposes. It does not mean fill cannot settle. Settlement may still result from:

Placing material without adequate compaction
Material that is too wet or otherwise difficult to work
A soft, disturbed, or organic subgrade
Different soil types mixed within a load
Buried roots, debris, or oversized clods
Water moving through or beneath the fill
Placement methods that do not match the project’s requirements

Topsoil is surface soil used as a growing layer. It commonly contains more organic matter than fill and is generally more suitable as a root zone, but quality varies substantially. Texture, nutrient content, pH, organic matter, drainage, weeds, debris, and contaminant status cannot be inferred from the word topsoil alone.

In its Michigan-focused purchasing guidance, Michigan State University Extension warns that topsoil does not provide a dependable product-quality definition and recommends inspecting material rather than assuming dark soil is rich or suitable (MSU Extension’s guidance on purchasing topsoil). Dark color may indicate organic matter, but it does not prove favorable texture, adequate nutrients, suitable pH, good drainage, or contaminant safety.

Organic matter can support roots, retain moisture, and contribute to soil biological activity. Those same compressible and degradable components generally make planting soil a poor unspecified base beneath surfaces that must resist settlement. The practical distinctions are:

Fill: bulk volume, rough grade, and support when properly selected and installed
Topsoil: the finished growing layer
Garden soil: often a supplier-specific blend of topsoil, compost, and other amendments
Compost: primarily an organic amendment rather than structural fill

Garden soil and compost should not be substituted for compactable base material unless a governing design expressly calls for that product. Conversely, mineral fill should not be expected to perform like a prepared planting mix merely because weeds can grow in it.

Terminology is inconsistent. One supplier’s “screened fill” may be fine-textured mineral soil; another’s may include an allowed amount of stone. “Garden soil” may be a rich planting blend or simply topsoil with a modest amendment. “Clean fill” can carry a supplier-specific or jurisdiction-specific meaning. An order should therefore describe the required function, source, processing, and verification—not only the marketing name.

Project-by-project material selection

The easiest way to resolve fill dirt vs topsoil is to start with the finished use and work downward.

Deep holes and substantial grade increases

Evaluate suitable fill for most of the lower volume. After placement and rough grading, install the finish material required by the surface use.

If the area will become lawn, the finish will normally be suitable topsoil or planting soil. If it will become a path or driveway, the finish may instead be a specified aggregate assembly. If it remains unplanted, fill may be the final material if it meets the project’s drainage, erosion, and stability needs.

Before filling a hole, determine why it exists. A depression caused by initial grading differs from one associated with buried organic material, a disturbed trench, erosion, or an unidentified subsurface problem. Adding soil without understanding the cause may produce only a temporary repair.

Deep repairs beneath lawns

A common landscaping sequence is:

Remove or manage unsuitable surface material.
Investigate the source of settlement or water where practical.
Place suitable fill below the intended root zone.
Compact and shape the fill as required for the project.
Add suitable topsoil.
Prepare the surface for seed or sod.

Commercial yard guidance likewise recommends fill for the lower portion of deep repairs and screened topsoil at the lawn surface (Serbu Sand & Gravel’s yard-material comparison). The point is to separate the bulk-fill function from the growing-layer function, not to impose one universal depth.

Shallow depressions in established turf

A shallow dip usually calls for surface repair or gradual topdressing rather than excavation-scale filling. Apply compatible material in controlled passes so grass blades remain exposed and can continue growing. If further correction is needed, allow the turf to recover before repeating the process.

There is no universal depth at which a repair changes from “topdressing” to “fill plus topsoil.” Turf species, grass condition, depression shape, soil texture, season, equipment, and drainage all affect the choice. A broad, gentle depression can require a different method from a narrow wheel rut with the same maximum depth.

If the lawn repeatedly sinks, investigate before adding another layer. Recurring settlement can indicate unsuitable original placement, buried debris, a disturbed trench, erosion, animal activity, or water movement.

New lawns

For a new lawn, first create a suitable subgrade at the intended rough elevation. Then establish a growing layer compatible with the turf and native soil.

Do not assume imported topsoil is ready for seed or sod. It may need grading, stone removal, organic amendment, lime, or fertilizer, but those decisions should follow inspection and preferably a soil test. Adding amendments without testing can be ineffective or create nutrient imbalances.

The final surface must also account for sod thickness, curbs, walks, drainage structures, and mower transitions. Ordering soil from one average depth may leave excessive material at fixed edges and too little in low portions.

Gardens and planting beds

Use inspected or tested planting soil rather than plain fill as the intended root zone. Purchased topsoil can be a component of the bed, but it is not automatically a complete garden mix. It may be low in nutrients, overly clayey, excessively sandy, poorly structured, or incompatible with the underlying soil.

If the source of imported soil is uncertain—especially for a food garden—ask the relevant local extension service, environmental authority, or qualified laboratory what source documentation or testing is appropriate. Screening alone cannot determine contaminant status.

Compost may improve planting soil when applied appropriately, but it is an amendment rather than a replacement for the mineral portion of soil. Fertility and amendment decisions should reflect the plants being grown and the results of a soil analysis.

Berms

A landscaped berm can use stable, suitable fill for the core and planting soil where roots will grow. This avoids constructing the entire landform from more compressible and typically more expensive planting material.

The berm still requires practical planning. Consider:

How water will flow around and off it
Whether the sides are vulnerable to erosion
How much the core may settle
Whether mowing equipment can traverse it
The rooting needs of the planned vegetation
Sight lines near driveways or roads
Effects on surrounding drainage

A berm is not merely a pile of soil. Its placement changes surface flow and the usable shape of the site.

Backfill

“Backfill” describes where material goes, not what the material must be. Backfill around a utility, foundation, septic component, retaining structure, removed pool, or landscape excavation may have substantially different requirements.

Use the material and placement method identified for the particular application. A soil that compacts firmly may still be wrong where free drainage is required. An open-graded drainage material may be unsuitable where the work instead requires dense, erosion-resistant support.

Patios, driveways, sheds, slabs, foundations, and roads

Do not assume ordinary fill dirt is acceptable merely because available equipment can compact it. These projects may require removal of unsuitable surface soil, defined aggregate gradations, moisture control, controlled placement, drainage provisions, or verification of the completed base.

For patios and driveways, specified aggregate may be preferable to either topsoil or soil fill. For sheds, follow the foundation design and applicable manufacturer or plan requirements. For slabs, foundations, and roads, use the construction documents and project-specific site recommendations.

This article cannot determine whether a particular soil is structurally suitable. That decision depends on the actual material, site conditions, loads, drainage, and governing project documents.

Retaining structures

Retaining-structure backfill must serve the wall design rather than a supplier’s broad definition of fill. Drainage zones, reinforcement areas, compaction methods, outlets, and retained height can all affect material selection.

Fine or clay-rich general fill may retain water and may be inappropriate in a designated drainage zone. Aggregate, drainage stone, select fill, or another specified material may be required. Do not replace designed components with an economical soil product unless the responsible designer or governing instructions permit it.

Wet or high-traffic areas

Where soil remains wet or receives repeated vehicle or equipment traffic, aggregate or a designed drainage section may be more effective than fill dirt or topsoil. Adding fine-textured soil can increase elevation without creating a drainage outlet, while topsoil may simply create a deeper saturated layer.

Determine whether the area needs grade correction, drainage, undercutting, separation, aggregate, stabilization, or some combination. Material selection should follow that diagnosis.

A four-question decision tree

Use these questions in order:

Must the area bear a meaningful load? If yes, stop choosing by retail soil label. Follow the specified base, subgrade, drainage, and verification requirements.
Must the area gain substantial elevation? If yes, evaluate suitable fill for the lower volume rather than using planting soil through the full depth.
Must the finished surface support plants? If yes, provide an appropriate root zone using inspected or tested topsoil or planting soil. If not, the finish may instead be aggregate, pavement, mulch, or another designed surface.
Must the work correct or preserve drainage? If yes, identify why water collects and where it can go. Neither “fill” nor “topsoil” guarantees good drainage.

A project can answer yes to all four questions. In that case, it needs a layered approach—not a winner in a two-product contest.

Using fill dirt and topsoil together

Combining fill and topsoil is common when an area needs both added elevation and a vegetated finish. The lower layer builds the landform; the upper layer supports roots.

A general landscaping sequence is:

Expose and assess the subgrade. Remove or manage vegetation, debris, buried organic matter, and visibly unsuitable material.
Investigate settlement and drainage. Determine why the elevation is low and where water can move.
Correct identifiable problems. This may involve removing weak material, addressing a damaged feature, improving drainage, or revising the proposed grade.
Place suitable fill in controlled layers.
Compact each layer as the project requires.
Establish rough grade. Reserve enough elevation for topsoil, sod, mulch, or another finish.
Create a transition between soil layers where appropriate.
Install and prepare the final growing layer.
Protect the growing layer from unnecessary equipment traffic.

When future settlement matters, fill should not simply be dumped to full depth and compacted only from the top. One commercial industry guide recommends approximately 4- to 6-inch layers, but actual loose-layer thickness depends on material, moisture, equipment, access, required density, and the governing specification (Soil Connect’s fill-placement discussion). Treat that range as attributed commercial guidance, not a universal field requirement.

There is likewise no single topsoil depth suitable for every lawn, vegetable bed, shrub, tree, or native planting. Rooting depth, underlying soil, drainage, irrigation, grade tolerances, and the intended plant community all matter.

A 4- to 6-inch topsoil layer is frequently suggested in commercial guidance for some lawn and landscape applications, but it is not a universal code or planting requirement (White Shovel Landscapes’ yard-leveling guidance). A light repair to existing turf may need far less material at one time, while an intensive planting area may require a deeper prepared root zone.

Also consider the boundary between imported topsoil and existing soil. Loose topsoil placed abruptly over a dense, smooth, or compacted surface can create a sharp transition for roots and water. Where site conditions and the planting plan permit, loosen the receiving surface and incorporate an initial layer rather than leaving two disconnected soil systems. MSU Extension specifically warns that a separate topsoil layer over dense existing soil can impede drainage and downward root growth.

Once topsoil is spread, keep loaders, trucks, and repeated wheel traffic off it where practical. Heavy shaping and bulk placement should be completed before the final growing layer is installed whenever sequencing allows.

Drainage and settlement: what the material names do not tell you

Neither fill dirt nor topsoil predicts drainage by itself.

Clay-rich fill may retain water and become difficult to work when wet. Sandy material may transmit water more readily but can compact, migrate, or erode differently.

Adding topsoil over dense soil does not automatically improve drainage. The new layer may absorb water initially, while the underlying restrictive layer still slows downward movement.

Before importing soil to fix puddles, investigate why water collects. Possible factors include:

A low finished grade
No workable surface outlet
Compacted native soil
A restrictive subsurface layer
Roof or pavement runoff entering the area
Erosion that removed surface material
A disturbed trench that settled
Blocked drainage infrastructure
Seasonal groundwater conditions

Evaluate where the revised surface will send runoff, especially near buildings, septic areas, utility corridors, drainage features, public ways, and neighboring land.

Near a building, avoid treating added soil as a complete drainage solution. Finished elevations, drainage paths, and clearances around walls, cladding, openings, and other components depend on the particular building and applicable local requirements. If those requirements are not known, obtain project-specific guidance before changing the grade.

Low-organic fill may reduce volume loss associated with decomposition, but it does not eliminate movement caused by:

Weak underlying soil
Poor placement control
Inadequate compaction
Unsuitable moisture
Freeze-thaw or wetting-and-drying effects
Inconsistent material
Unremoved roots or debris
Erosion or internal water movement

Persistent pooling, recurring settlement, active erosion, substantial elevation changes, foundation drainage work, and retaining-structure backfill are no longer simple product-selection questions. They may require assessment by a contractor, designer, geotechnical professional, drainage specialist, or applicable local authority, depending on the project.

Clean, screened, structural, and engineered fill are not interchangeable

Supplier terminology can start a conversation, but it should not replace a material description, test result, specification, or acceptance document.

Screened material has passed through a screen that separates particles, roots, clods, rocks, or debris according to the opening used. Screening can make material more uniform and easier to rake, spread, or finish.

Screening does not verify:

Fertility
Nutrient content
pH
Organic-matter content
Weed seeds or pathogens
Heavy metals or chemical contaminants
Moisture suitability
Compaction characteristics
Bearing performance
Compliance with a structural specification

A screen is a size-separation tool, not a laboratory.

Clean fill is more complicated. Its meaning may vary among suppliers and jurisdictions. One seller may mean visually free of trash; another may refer to a defined acceptance process. A verbal assurance that soil is “clean” does not identify what substances were evaluated, what limits applied, or whether the material is acceptable at the destination.

Structural fill or engineered fill should mean material selected, installed, and verified against project requirements—not merely soil marketed as useful for filling. Depending on the project, those requirements may address composition, gradation, moisture, placement, density, and testing. This guide does not establish universal acceptance criteria.

Projects may specify select fill, compactable fill, crushed aggregate, drainage stone, or aggregate base instead of ordinary fill dirt.

Material label	Primary intended function	What should be verified
Ordinary fill	Add volume, fill depressions, establish rough grade	Source, composition, debris, moisture, compactability, drainage behavior, and site suitability
Screened fill	More uniform fill that is easier to spread and finish	Screen size, allowed stone, source, visible debris, and performance requirements
Clean fill	Fill represented as meeting a cleanliness criterion	Exact definition, destination requirements, source records, and any required testing
Structural or engineered fill	Support loads as part of a designed and controlled installation	Material specification, placement method, moisture control, acceptance criteria, and field verification
Topsoil	Surface growing layer	Texture, pH, organic matter, nutrients, debris, weeds, contaminants, and compatibility
Garden soil	Planting blend, often topsoil plus amendments	Ingredients, nutrient levels, soluble salts where relevant, compost maturity, drainage, and intended plants
Compost	Organic soil amendment	Feedstock, maturity, nutrients or salts, application rate, and intended use
Aggregate	Base, drainage, separation, or load distribution depending on gradation	Material type, particle-size distribution, cleanliness, thickness, compaction, confinement, and drainage role

The key distinction is between processing and verification. Screening changes particle-size distribution. Fertility testing evaluates growing conditions. Environmental testing evaluates specified contaminants. Geotechnical testing evaluates properties relevant to earthwork. None automatically substitutes for another.

How to inspect, order, and calculate bulk soil

Bulk soil ordering begins with geometric volume:

Cubic yards = length in feet × width in feet × depth in feet ÷ 27

For irregular areas, divide the site into manageable shapes, calculate each section, and add the results. Use an average depth only when it reasonably represents the planned grading.

For example, raising 1,000 square feet by 6 inches gives:

Convert 6 inches to 0.5 feet
Multiply 1,000 square feet by 0.5 feet = 500 cubic feet
Divide 500 by 27 = approximately 18.5 cubic yards

That is the geometric volume before any allowance for compaction, settlement, shaping, irregular grade, spillage, or measurement error. The same cubic-yard formula is presented in commercial bulk-fill estimating guidance (Mulch and More’s fill-soil guide).

Do not apply one universal extra percentage. The appropriate allowance depends on:

Whether the dimensions describe loose or finished volume
Expected compaction
Material type and moisture
Existing surface irregularity
Side-slope shaping
Settlement expectations
Undercutting or removal of unsuitable material
Handling loss and spillage
Measurement accuracy
Whether the supplier sells by volume or weight

Confirm the supplier’s actual vehicle capacity, loading practice, and delivery minimum. “One truckload” is not a dependable unit across vehicle types, soil densities, moisture conditions, and suppliers.

Pre-order checklist

Before ordering, ask:

What is the intended use? Lawn base, berm core, general grading, garden, backfill, patio base, or structural earthwork?
Where does the material come from? Is the source consistent, and can it change between deliveries?
What is its approximate composition or gradation? Is it primarily clayey, sandy, silty, gravelly, or mixed?
Has it been screened? If so, through what screen size?
What visible material is permitted? Ask about roots, asphalt, concrete, brick, wood, glass, plastic, and oversized stone.
What does “clean” mean? Request the supplier’s definition and any applicable documentation.
Is source or contaminant information available? Determine what documentation is appropriate for the intended destination.
For topsoil, is an analysis available? Ask about texture, pH, organic matter, nutrients, soluble salts where relevant, and any available contaminant results.
What is the current moisture condition? Saturated material can be difficult to spread or compact and may affect delivered weight.
Can a sample be inspected? View the stockpile or obtain a representative sample when possible.
What access does delivery require? Confirm gate width, overhead clearance, turning room, surface condition, and dumping location.
Does the supplier spread material? Clarify whether the price covers dumping only or includes spreading or machine work.
What fees apply? Ask about delivery zones, minimum orders, waiting time, rejected loads, difficult access, and split loads.
What are the rejection terms? Know what happens if the material differs materially from the order.

MSU Extension recommends inspecting bulk topsoil before purchase when possible rather than relying on color or the product name alone.

Delivery inspection checklist

Inspect each load before it is widely distributed. Check for:

Consistency with the ordered product
Unexpected roots or woody material
Construction debris
Glass, plastic, metal, asphalt, brick, or concrete
Excessive clods or oversized rocks
Unusual odors
Material so saturated that it cannot be placed as intended
Dramatic color or texture changes within the load
Unexplained variation between successive loads
Documentation that does not match the delivery

Visual inspection and odor can identify reasons to reject or investigate a load, but they cannot prove that soil is contaminant-free. Where contaminant status matters, rely on the documentation or testing appropriate to the site and intended use.

Photograph questionable material while it remains in the truck or in a contained pile.

Total project cost also includes delivery distance, access, equipment, spreading, compaction, testing, disposal of unsuitable material, and correction of drainage or subgrade problems. Compare the delivered scope rather than only the advertised price per cubic yard.

When a simple landscaping decision becomes a technical project

Routine landscaping can include light topdressing, minor bed shaping, and shallow surface repairs that do not support structures or materially change drainage. The decision becomes more technical when the work must:

Support a building, pavement, wall, or repeated vehicle load
Retain soil
Alter a significant drainage path
Change site elevation substantially
Affect a steep or visibly unstable slope
Interact with a foundation, septic component, utility, or easement
Receive imported material for which environmental acceptance matters

At that point, a general fill dirt vs topsoil comparison is not enough. Ask the applicable local authority or project professional what permits, documentation, erosion controls, drainage review, property-line considerations, or material acceptance requirements apply. Those requirements vary by location and cannot be established by a supplier’s practices in another jurisdiction.

Project-specific design or professional review may be appropriate around:

Foundations and slabs
Public or private roads
Retaining structures
Steep or unstable slopes
Septic systems and reserve areas
Drainage easements
Flood-prone land
Large fills or cuts
Recurring settlement
Concentrated runoff
Suspected contaminated soil

Before excavation or a substantial grade change, determine and follow the applicable local process for identifying buried services. Also account for valves, cleanouts, boxes, drainage structures, tanks, lids, and other access points that added soil could conceal or obstruct.

Structural earthwork may require specified material, moisture conditioning, density verification, proof rolling, or geotechnical observation. Which measures apply depends on the project documents, site conditions, authority, and type of construction. General landscaping guidance cannot establish those requirements.

Stop work and seek project-specific clarification if:

The material origin is unknown or changes without explanation.
The soil contains suspicious debris or unusual odors.
Contamination is suspected.
Settlement continues after repeated repairs.
Runoff cannot be managed within the intended design.
A slope shows cracking, slumping, or active erosion.
Excavation exposes unidentified services or buried structures.
The work may conflict with a drainage feature, easement, or septic area.
The delivered material cannot satisfy the project specification.
The only evidence of structural suitability is a verbal supplier description.

Frequently asked questions

Can grass grow directly on fill dirt?

Sometimes, but establishment is less reliable than in a suitable growing layer. Fill may be low in organic matter and nutrients, compacted, uneven in texture, or difficult for roots to penetrate. Grass surviving on a particular fill does not prove that it will produce a durable lawn.

For a deep lawn repair, use suitable fill to create most of the elevation and finish with compatible topsoil before seeding or laying sod. For an existing lawn with a shallow depression, gradual topdressing may preserve the turf better than covering it with a thick layer.

How much topsoil should go over fill dirt?

There is no universal depth. The correct growing layer depends on whether the surface will support turf, vegetables, perennials, shrubs, trees, or another plant community. Native soil texture, compaction, drainage, irrigation, and expected rooting depth also matter.

Commercial guidance often cites 4 to 6 inches for some lawn and landscape applications, but that is a planning reference rather than a universal requirement (Harbor Soils’ fill dirt and topsoil comparison). Existing lawns receiving topdressing generally need lighter applications at one time, while planting beds may need a deeper prepared root zone or incorporation into the existing soil.

Does screened fill or screened topsoil mean the material is clean and safe?

No. “Screened” means the material passed through a screen that separated particles larger than the selected opening. This can improve uniformity and remove some larger rocks, roots, clods, or debris, but it does not establish contaminant safety, fertility, pH, pathogen status, or engineering performance.

Ask separately about source documentation, environmental acceptance requirements, soil analysis, and structural testing. Those checks answer different questions from screening.

Can ordinary fill dirt go under a patio, driveway, shed, or slab?

Only if the governing design or specification permits that particular material and installation. Ordinary landscaping fill should not be assumed to qualify.

A project may instead require select fill, crushed aggregate, drainage stone, a defined aggregate base, moisture control, controlled placement, verification, or removal of unsuitable subgrade. The appropriate assembly depends on loads, soil, drainage, climate, and the structure being supported.

How many cubic yards of fill dirt or topsoil do I need?

Multiply length in feet by width in feet by depth in feet, then divide by 27 to convert cubic feet to cubic yards. For variable grades, divide the area into sections or use a defensible average depth.

For 1,000 square feet raised by 6 inches, the calculation is 1,000 × 0.5 ÷ 27, or approximately 18.5 cubic yards before project-specific allowances (White Shovel Landscapes’ volume guidance). Adjust the order for applicable compaction, shaping, irregular grade, settlement, handling loss, and measurement uncertainty, then confirm how the supplier measures and delivers the product.

The final decision

Choose in three parts:

Use suitable fill to create bulk volume and rough grade.
Use verified topsoil or planting soil where roots must grow.
Use both when the finished area needs additional elevation plus vegetation.

Screening is not testing, ordinary fill dirt is not automatically engineered fill, and topsoil does not guarantee fertility or drainage. When the work supports loads, retains soil, changes significant drainage, or interacts with structures and buried infrastructure, follow the site-specific design and applicable local requirements rather than relying on a supplier label.