Topsoil, garden soil, and potting soil sit side by side in the garden center, and the labels do not tell you which one belongs in your lawn, your raised bed, or your pots. The names also change between countries. In the UK, “garden soil” usually means the soil already in your plot, and “potting compost” is the nearest match to US potting soil.
This guide defines each material once, compares them in a single table, and matches each one to a job: lawns and grading, in-ground beds, raised beds, containers, and seed starting. It also covers compost, bagged raised bed mix, and John Innes. Where university extension services and gardening bodies disagree, such as raised bed ratios and soil in pots, you will see the range rather than one confident number.
Then comes the math. You will get plain formulas for cubic yards, cubic feet, liters, and cubic meters, four worked examples (two US, two UK), and a cost method you can repeat with today’s prices. The matching tools on this site are the Topsoil Calculator, the Raised Bed Soil Calculator, the Soil Mix Ratio Calculator, and the Potting Soil Calculator.
The Short Answer: Match the Soil to the Job
Topsoil is natural surface soil for filling, grading, lawns, and in-ground beds. Garden soil is a bagged blend sold for in-ground and raised beds, and its recipe changes by brand. Potting soil, also called potting mix, is a mostly soilless blend made for containers.
The rule that holds across the extension sources we reviewed is simple. Use potting mix in pots, and use topsoil or garden soil in the ground. Do not fill pots with garden soil or topsoil on their own, because they compact and drain poorly in a container.
What Topsoil Is and What the Label Leaves Out
Topsoil is the upper layer of natural soil, usually darker than the soil below because it holds more organic matter. It is the material to buy when you need to fill a hole, level a low spot, build a lawn base, or top up a bed. For a deeper definition, see our guide on what topsoil is.
The word on the bag is a weaker promise than it sounds. Utah State Extension notes that much material sold as topsoil is actually subsoil. Maryland reports that it does not regulate topsoil sales, and Connecticut’s soil-testing lab says the same about marketing standards.
Natural topsoil thickness also varies by site. Utah State describes a typical range of 2 to 10 inches in Utah, and that number is not a national rule. Keep two ideas apart: how thick the natural layer is on your land, and how deep you choose to spread the topsoil you buy.
Bulk Topsoil Versus Bagged Topsoil
Bulk topsoil is sold by the cubic yard, tonne, or cubic meter and is delivered loose or in bulk bags. Bagged topsoil is sold by the cubic foot or liter and carries a label with ingredients. Bulk suits whole lawns and large beds, while bags suit patches, small holes, and small beds.
Bagged US Topsoil Can Be Mostly Peat
Read the ingredient list, because a bag called topsoil may not be mineral soil. One retailer listing for Scotts Premium Topsoil, read in October 2026, names peat, composted forest products, and rice hulls, and says “in-ground use only”. Illinois Extension also notes that some bagged topsoil is mostly sedge peat.
That does not mean every bagged topsoil is peat. It means the label matters more than the name.
UK Topsoil, BS 3882, and the Edition Question
In the UK, topsoil is traded against a British Standard, BS 3882. The British Standards Institution lists the 2015 edition as current. Many suppliers and the Royal Horticultural Society (RHS) still describe premium, general-purpose, and economy grades.
We have not printed pH or nutrient limits here, because the standard itself is paywalled. Ask your supplier which edition and grade they sell, and ask for the analysis in writing.
How to Check Topsoil Quality Before You Buy
Good topsoil looks dark and crumbly and smells earthy, according to the University of Maryland. Ask the supplier where it came from, whether it was screened, and whether they have test results. A short visit to the pile tells you more than a product page does.
Weeds, Fill, and Contaminants
Imported topsoil can carry weed seed, building-site fill, and unwanted roots. The RHS warns about Japanese knotweed and couch grass, and Iowa State warns about lead and pesticides in imported topsoil. If you grow food, Maryland advises testing native soil for lead.
Compost and soil mixes can also carry persistent herbicides that survive composting. Oregon State Extension reports that herbicides such as clopyralid and aminopyralid can remain active in soil for years, and it describes a simple pea-seedling test for suspect material.
The Jar Test and Lab Tests
A jar test shows your soil texture at home. Clemson Extension has you fill a jar about one third with sifted soil, add water, and shake. You then measure sand at 1 minute, silt at 2 hours, and clay at 48 hours.
A lab test goes further. Utah State publishes numeric topsoil criteria, such as an ideal pH of 5.5 to 7.5 and at least 2 percent organic matter. Treat those as one state’s guidance for alkaline, salty soils, not as a national standard.
What Garden Soil Is
Garden soil is a retail category, not a standard. It is a bagged product sold for in-ground beds and raised beds. The ingredients differ by brand, so the label tells you more than the name does.
Sources even disagree on what is inside. Some articles call garden soil a blend of topsoil, compost, and manure. Several product ingredient lists, such as Espoma’s and Miracle-Gro’s, show mostly composted forest products, peat, compost, manure, and perlite.
Maryland notes that bagged “organic soil” usually contains no real topsoil.
“Garden Soil” in the UK Usually Means Your Own Soil
In British usage, garden soil is the ground in your garden. It is not usually a bag you buy. This is the biggest false friend between the two countries, and it explains why UK pages compare topsoil with compost instead of with garden soil.
What Potting Soil Is
Potting soil is a blend made for containers. Illinois Extension, Iowa State, and Mississippi State describe it as soilless, built from peat or coir, bark, perlite, and vermiculite. Espoma’s potting mix lists no mineral topsoil at all, despite the name.
That structure is the point. Light, airy media hold water and drain in a pot, where heavy mineral soil would pack down. Clemson also notes that soilless media need a different lab test than mineral soil, because they can hold far more organic matter.
Potting Soil, Potting Mix, and Potting Compost
Several popular articles treat “potting soil” and “potting mix” as the same thing. A few brands try to separate them, and the lines are not consistent. We treat them as retail labels for container media and suggest you check the ingredient list.
In the UK, the nearest terms are potting compost and multi-purpose compost. Seed compost is a finer product for starting seedlings.
Is Potting Soil Sterile?
Not as a rule. Some brands heat-treat their mixes and some do not, and the sources we reviewed do not agree. Many mixes are low in weed seed, but read the label rather than assuming.
Where Compost, Raised Bed Mix, and John Innes Fit
Compost is an amendment, not a stand-alone fill. Oregon State advises against filling a raised bed with compost alone, partly because it settles as it breaks down. Compost can also carry salts, and it can carry herbicide residue if the source was contaminated.
Bagged raised bed mix is usually soilless, according to Mississippi State Extension, which means it is lighter and often costs more than a topsoil and compost blend. In the UK, John Innes composts are loam-based and graded as No 1, No 2, and No 3 for increasing fertilizer levels. The RHS notes there is no legally binding standard for what a John Innes product must contain.
Side-by-Side Comparison Table
The table below shows typical roles, not standards. Ingredients vary by brand, so read the label. Prices are left out on purpose and appear in the cost section instead.
| Material | What it is | Contains mineral soil? | Best for | Avoid for | Main watch-out | Sold as |
|---|---|---|---|---|---|---|
| Bulk topsoil | Screened natural surface soil | Yes, quality varies | Fill, grading, lawn base | Pots on its own | Origin, weeds, contaminants | Cubic yard, tonne, m³ |
| Bagged topsoil (US) | Bagged product sold as topsoil | Depends on the label | Lawn repair, small holes | Pots on its own | Can be mostly peat | Cubic feet |
| Bagged garden soil (US) | Blend for in-ground and raised beds | Depends on the label | In-ground beds, some raised beds | Pots on its own | Recipe varies by brand | Cubic feet |
| Potting soil or mix (UK: potting or multi-purpose compost) | Soilless container blend | Usually no | Containers, houseplants | Sole fill for deep beds | Dries out, costs more | Cubic feet, quarts, liters |
| Compost (UK: garden compost, soil improver) | Decomposed organic matter | No | Amending soil | Sole bed fill | Salts, herbicide residue | Cubic feet, liters, bulk |
| Bagged raised bed mix | Ready blend for filled beds | Usually no | Filled raised beds | Heavy-use lawns | Cost, drying out | Cubic feet |
| John Innes (UK) | Loam-based compost, graded No 1 to 3 | Yes, loam | Long-term pots | Seed starting (use seed compost) | Product quality varies | Liters |
Which Soil to Use for Each Job
Lawns, Grading, and Filling Holes
Topsoil is the material for lawns, low spots, and grading. The RHS suggests spreading at least 10 cm (4 inches) for lawns, and US sources commonly give 3 to 6 inches for a new lawn. Our lawn soil guide goes into seedbeds, patching, and topdressing in detail.
In-Ground Beds and Vegetable Gardens
For beds in the ground, work compost into your native soil, or mix a bagged garden soil into it. The RHS suggests about 20 cm (8 inches) of topsoil for new beds. Test first if you grow food, because lead and herbicide residues are problems you cannot see.
Seed Starting and Houseplants
Seeds and houseplants do best in a soilless mix made for containers. In the UK, the RHS recommends a fine seed compost for seedlings, and says multi-purpose compost can be too rich for them. For plants in pots, see the Potting Soil Calculator for quantities.
Raised Bed Fill: Where the Sources Disagree
Raised bed advice is where the sources split the most. Some of that is climate, since a wet-summer state and a semi-arid state will not give the same advice. Some of it is aim, because a bed on lawn and a bed on pavement behave differently.
The chart below lines up the recipes we found, so you can see the spread at a glance.
Ratios by Source and a Safe Starting Range
For a deep bed built on soil, the extension and RHS recipes cluster around half to two thirds topsoil, with the rest compost, and sometimes sand. The RHS adds sharp sand at 7 parts topsoil, 3 parts organic matter, and 2 parts sand. Oregon State and Colorado State advise much less compost, for reasons tied to local soils.
The right split depends on your topsoil’s quality, your compost’s maturity and salt level, and your climate. Treat 2 parts topsoil to 1 part compost, and 1 to 1, as two reasonable starting points rather than rules. The Soil Mix Ratio Calculator splits a volume you already know into the parts you choose.
Potting mix as raised bed fill is contested. The University of Minnesota says it dries out too fast, while the University of Maryland allows soilless mix plus compost for beds on pavement. Beds made only of compost or soilless mix dry out faster than beds with mineral soil.
Bed Depth by Crop
Maryland recommends at least 8 inches for leafy greens, beans, and cucumbers. It recommends 12 to 24 inches for peppers, tomatoes, and squash. The RHS gives 30 cm for salad crops and strawberries, and 45 cm or more for fruit bushes.
Containers: Why Pots Need Potting Mix
In a pot, drainage and air matter more than anything else. Illinois, Clemson, and the University of New Hampshire all say garden soil compacts in containers and holds too much water. Iowa State and the University of Massachusetts advise against mineral soil alone for the same reason.
Two common habits do not help. A layer of gravel in the bottom of a pot does not improve drainage, and it can raise the waterlogged zone. Overfilling also hurts, so leave about 1 inch below the rim for watering, as Illinois suggests.
When a Little Soil in the Mix Is Acceptable
Some sources allow a limited share of garden soil in a large pot, mostly to add weight so tall pots stay upright. Illinois describes stretching a soilless mix with about 25 percent soil, or an equal-parts recipe of garden soil, peat, and perlite. Other sources, including the University of New Hampshire, say not to use it at all, so the safe summary is “not alone, and not as a default”.
How Much Soil Is the Ceiling
Where sources allow soil in a soilless mix, they cap it at roughly a fifth to a quarter by volume. University of California Orange County says up to 20 percent, and Illinois gives about 25 percent. Other pages quote caps of their own without naming a source, so we do not repeat them.
How Much Soil You Need
Every soil job starts with the same volume formula. Measure the area and the depth in compatible units, multiply, and convert.
Volume = Length × Width × Depth
Where:
- Length and Width = the size of the area
- Depth = the thickness of the soil layer, in the same unit
For US jobs there is a shortcut for cubic yards. It works because 1 cubic yard is 27 cubic feet, and 27 × 12 inches = 324.
Cubic Yards = Area (sq ft) × Depth (inches) ÷ 324
For bags, divide by the printed bag volume and round up.
Bags = Volume Needed ÷ Volume Per Bag, rounded up
The Topsoil Calculator does these steps for you from width, length, and depth. It shows volume, weight, bags, and cost. The Raised Bed Soil Calculator returns volume, bags, and an optional cost for a bed.
Settling, Margins, and Bag Counts
Soil settles after you water it, and compost-rich or peaty material settles more. We could not find a sourced settling percentage, so we do not quote one. Choose a margin that fits your material, and remember that the printed bag volume is a label figure, not a promise about the volume once settled.
Bulk Bag Sizes Differ by Supplier
UK suppliers quote bulk bags anywhere from about 0.6 m³ to about 1 m³. Never assume a standard size. Read the supplier’s stated volume, because the same job can need four bags from one seller and seven from another.
Worked Examples
Each example below shows the formula, the arithmetic, and what the result means. The inputs are illustrative, not typical sizes.
Example 1: A US Raised Bed Filled With Topsoil and Compost
Take a bed 4 ft wide and 8 ft long, filled 12 inches (1 ft) deep. A 12-inch depth suits peppers, tomatoes, and squash, according to Maryland.
Volume = 4 × 8 × 1 = 32 cubic feet
Cubic Yards = 32 ÷ 27 = 1.19 cubic yards
Now split that volume. The table shows three common splits from the sources above. The two parts always add back to 32 cubic feet.
| Topsoil : compost split | Topsoil | Compost | Total |
|---|---|---|---|
| 70 : 30 (Iowa State) | 22.4 cu ft | 9.6 cu ft | 32.0 cu ft |
| 2 : 1 (two thirds and one third) | 21.33 cu ft | 10.67 cu ft | 32.0 cu ft |
| 1 : 1 | 16.0 cu ft | 16.0 cu ft | 32.0 cu ft |
Bags depend on the bag size you buy. For 32 cubic feet of fill, you need 16 bags of 2 cubic feet, 22 bags of 1.5 cubic feet (21.33 rounded up), 32 bags of 1 cubic foot, or 43 bags of 0.75 cubic feet (42.67 rounded up). Sixteen 2-cubic-foot bags of a garden soil at $9.83 each would cost 16 × $9.83 = $157.28, as an illustration of the method only.
Example 2: A US Lawn Base
Take a lawn 25 ft by 50 ft. First find the area, then the volume at the depth you choose.
Area = 25 × 50 = 1,250 sq ft
At 4 inches: Volume = 1,250 × 4 ÷ 12 = 416.7 cubic feet = 15.43 cubic yards. At 6 inches: Volume = 1,250 × 6 ÷ 12 = 625 cubic feet = 23.15 cubic yards.
Depth is the biggest lever. Going from 4 to 6 inches adds 7.7 cubic yards, so decide on the depth first and then run the Lawn Topsoil Calculator for your own yard.
Example 3: A UK Raised Bed in Liters and Cubic Meters
Take a bed 1.2 m wide and 2.4 m long, filled 0.3 m deep.
Volume = 1.2 × 2.4 × 0.3 = 0.864 m³ = 864 liters
That is about 1.13 cubic yards, or 30.5 cubic feet. The RHS raised bed recipe is 7 parts topsoil, 3 parts organic matter, and 2 parts sharp sand, which is 12 parts in all.
Topsoil = 864 × 7 ÷ 12 = 504 liters
Organic matter = 864 × 3 ÷ 12 = 216 liters
Sharp sand = 864 × 2 ÷ 12 = 144 liters
The three add up to 864 liters. In 50-liter bags, 864 ÷ 50 = 17.28, so you need 18 bags.
The RHS also says to stop about 5 cm below the rim, which means a fill height of 0.25 m. Then 1.2 × 2.4 × 0.25 = 0.72 m³ = 720 liters, split into 420, 180, and 120 liters, or 15 bags of 50 liters. Leaving the headspace saves three bags.
Example 4: A UK Lawn Base and Bulk Bag Size
Take a lawn of 40 m² and spread topsoil at the RHS minimum of 10 cm (0.1 m).
Volume = 40 × 0.1 = 4.0 m³
The number of bulk bags depends on the volume each bag holds. At 0.6 m³ per bag, 4.0 ÷ 0.6 = 6.67, so 7 bags.
At 0.75 m³ it is 5.33, so 6 bags, and at 1.0 m³ it is 4 bags. Check the stated volume before you order.
A Quick Pot Example
A nominal 5-gallon container holds 5 × 231 ÷ 1,728 = 0.67 cubic feet, which is about 18.9 liters. Leave the inch of headspace below the rim, so the potting mix you actually need is a little under that. The Potting Soil Calculator handles pots and grow bags by gallon size.
Bulk Versus Bagged: What Changes the Cost
Bulk topsoil usually costs far less per cubic yard than bags, but delivery and minimum loads change the total. One cost guide, LawnLove, puts bulk topsoil at $10 to $50 per cubic yard plus $80 to $170 for delivery. That is a commercial blog, so treat its ranges as indicative.
Bagged prices are easier to read off a shelf, and the same arithmetic puts them on a cubic-yard basis.
Cost Per Cubic Yard, Step by Step
Cost per Cubic Yard = (Price ÷ Bag Volume in cu ft) × 27
For example, a 0.75 cubic foot bag of Scotts Premium Topsoil at $2.79 on sale works out to 2.79 ÷ 0.75 = $3.72 per cubic foot, and $3.72 × 27 = $100.44 per cubic yard. The table below runs the same method on four products, using prices read in October 2026.
| Product (retailer) | Bag size | Price | Cost per cu ft | Cost per cu yd |
|---|---|---|---|---|
| Scotts Premium Topsoil (Tractor Supply), sale | 0.75 cu ft | $2.79 | $3.72 | $100.44 |
| Scotts Premium Topsoil (Tractor Supply), regular | 0.75 cu ft | $3.99 | $5.32 | $143.64 |
| Miracle-Gro Garden Soil (Home Depot) | 2 cu ft | $9.83 | $4.92 | $132.71 |
| Miracle-Gro Organic Raised Bed Soil (Tractor Supply), sale | 1.5 cu ft | $9.09 | $6.06 | $163.62 |
| Miracle-Gro Organic Raised Bed Soil (Tractor Supply), regular | 1.5 cu ft | $12.99 | $8.66 | $233.82 |
| Miracle-Gro Potting Mix (Walmart) | 2 cu ft | $14.38 | $7.19 | $194.13 |
These are indicative snapshots from one day, not typical prices, and listings change or sell out. We did not find a dependable current UK shelf price, so we do not give one. To price a UK job, divide the supplier’s price by the stated volume in cubic meters.
The Topsoil Cost Calculator and the Bags of Topsoil Calculator run this comparison with your own quotes.
US and UK Terms for the Same Materials
The same words mean different things on each side of the Atlantic, and “compost” is the trickiest. In the UK it can mean a bagged growing medium, while in the US it means decomposed organic matter. Use the table to translate.
| UK term | Nearest US term | Note |
|---|---|---|
| Topsoil (traded to BS 3882) | Topsoil, screened topsoil | The sources we reviewed found no US federal standard |
| Garden soil (your own plot) | Native soil | In the US, “garden soil” is a bagged product |
| Potting compost, multi-purpose compost | Potting soil, potting mix | Mostly soilless; check for a peat-free label |
| Seed compost | Seed-starting mix | Finer and lower in nutrients |
| John Innes No 1, 2, 3 | No direct equivalent | Loam-based, graded by fertilizer level |
| Garden compost, soil improver | Compost, soil amendment | Not a stand-alone bed fill |
| Bulk bag (about 0.6 to 1 m³) | Bulk bag, cubic yard | 1 cubic yard = 0.765 m³ |
| Liters, m³, cm | Quarts or gallons, cu ft or cu yd, inches | 1 cubic foot = 28.3 liters |
One more UK point: the RHS says that if a bag does not say peat-free, it most likely contains peat. We do not state the legal status of peat sales, because it was still changing in the sources we could check.
Topsoil, Garden Soil, and Potting Soil, Summed Up
Pick the soil by the job. Topsoil is for filling, grading, lawns, and beds in the ground. Potting mix is for containers and seed trays.
Garden soil sits in between, and the label tells you what it really is.
For raised beds, expect sources to disagree, and start from half to two thirds topsoil with compost for the rest. Then work out the volume with the formulas above or the Raised Bed Soil Calculator. Check the label, ask your supplier for the bag or bulk volume, and buy a margin that suits your material.
Frequently Asked Questions
Is topsoil the same as garden soil?
No. Topsoil is natural surface soil, while garden soil is a bagged product whose recipe varies by brand, and several ingredient lists show mostly composted forest products, peat, and compost. In the UK, “garden soil” usually means the soil already in your plot. Read the label either way.
Can I use topsoil instead of garden soil?
Often yes for in-ground beds, but most extension sources have you blend topsoil with compost rather than use it alone. Test imported topsoil for contaminants first, especially if you grow food. Bagged topsoil can be mostly peat, so check the ingredients.
Can I use potting soil in the ground or in raised beds?
It is contested for raised beds. The University of Minnesota says potting mix dries out too fast, while the University of Maryland allows soilless mix plus compost at 1 to 1 for beds built on pavement. For beds in the ground, native soil or topsoil improved with compost is the usual advice.
Can I use garden soil or topsoil in pots?
Not on their own. Illinois, Iowa State, the University of Massachusetts, and the University of California all say they compact and drain poorly in containers. Sources that allow soil in a soilless mix cap it at roughly a fifth to a quarter by volume, and others say none.
Can I mix topsoil and potting soil?
Yes, in limited amounts and for a reason. In large pots, the sources that allow soil keep it to about a fifth to a quarter of the mix. In deep raised beds on pavement, Maryland allows topsoil up to about 20 percent of the fill, blended with soilless mix and compost.
How much topsoil do I need in cubic yards or cubic meters?
Multiply length × width × depth in the same units. In US units, Cubic Yards = Area (sq ft) × Depth (inches) ÷ 324. For example, 1,250 sq ft at 4 inches needs 15.43 cubic yards, or use the Topsoil Calculator.
Is bulk topsoil cheaper than bagged?
Usually, per cubic yard. One cost guide quotes bulk topsoil at $10 to $50 per cubic yard plus $80 to $170 delivery, while the bagged products we checked in October 2026 worked out to roughly $100 to $234 per cubic yard. Delivery and minimum loads can change the answer for small jobs, and all prices here are indicative.
How deep should topsoil be for a lawn or vegetable bed?
The RHS suggests at least 10 cm (4 inches) for lawns and about 20 cm (8 inches) for new beds, and US sources commonly give 3 to 6 inches for a new lawn. For raised vegetable beds, Maryland recommends at least 8 inches for greens, beans, and cucumbers, and 12 to 24 inches for peppers, tomatoes, and squash.
What is the difference between topsoil and compost?
Topsoil is natural mineral soil, while compost is decomposed organic matter used to improve soil. Oregon State advises against filling a raised bed with compost alone. In the UK, “compost” can also mean a bagged potting or multi-purpose growing medium.
Is UK potting compost the same as US potting soil?
They are close but not identical. Both are mostly soilless container media, and the UK also sells loam-based John Innes composts, which have no direct US equivalent. Check the label for peat-free wording, since the RHS says a bag that does not say peat-free most likely contains peat.
Daniel
Founder & Editor – TopSoilCalcOnline.com
Daniel is the founder and primary editor of TopSoilCalcOnline.com, a practical resource built to help homeowners, landscapers, and contractors accurately calculate topsoil, compost, and soil mix requirements. With hands-on experience in lawn preparation, raised beds, topdressing, and bulk soil planning, Daniel focuses on turning complex volume calculations into simple, reliable tools. Every calculator and guide on this site is designed to reduce material waste, prevent over-ordering, and help users plan landscaping projects with confidence and precision.