The properties a topsoil specification makes you measure, what a texture class name really claims, and the one failure mode you have to test for yourself.
Use the Topsoil Calculator — work out cubic yards from area and depth.
If a landscape contract calls for topsoil meeting ASTM D5268, check the year. The active edition today is ASTM D5268-23, Standard Specification for Topsoil Used for Landscaping and Construction Purposes. The 2019 revision (D5268-19e1) and the 2022 revision that followed it are both historical. A specification drafted a few years ago that names D5268-19 is two revisions out of date, and a bare designation on a delivery ticket tells you nothing unless the edition year travels with it.
Its scope is narrower than the word 'specification' suggests: it sets out how to evaluate a soil physically, for use as topsoil where things are meant to grow. Evaluating a soil against it means determining organic matter content, moisture content, the inorganic fractions of sand, silt and clay, pH, salt content, cation exchange capacity, and deleterious materials, which the standard identifies as rocks, gravel, slag, cinder, roots and sod.
It is equally explicit about where it stops: the specification does not cover a determination of nutrients, nor their availability. This is a voluntary consensus specification, not a regulation. It binds a supplier only when a contract invokes it. It is also not free to read, which is why no numeric composition limits from it appear below. If your spec cites the standard, buy the current edition rather than trusting anybody's summary of it, including this one.
Texture class names come from the USDA soil texture classes in the Soil Survey Manual, Agriculture Handbook No. 18, fourth edition, issued March 2017 with minor amendments in February 2018. That edition supersedes the 1962 and 1993 manuals. Chapter 3 defines twelve classes and gives each of them arithmetic boundaries.
Sandy loams, under those definitions, have 7 to less than 20 percent clay and more than 52 percent sand, with the silt percentage plus twice the clay percentage at 30 or more; or, alternatively, less than 7 percent clay and less than 50 percent silt, again with silt plus twice clay at 30 or more. Loam is 7 to less than 27 percent clay, 28 to less than 50 percent silt, and 52 percent sand or less. These are definitional boundaries in a classification system, not quality grades.
Two consequences matter at the yard. Texture is defined on the fine earth only, meaning particles smaller than 2 mm; anything 2 mm or larger — rock fragment, pararock fragment or manufactured artifact — is excluded and sits outside the class entirely, so a texture name says nothing about how stony a pile is. And texture is a particle-size statement and nothing more. It carries no information about pH, salts, organic matter, or anything dissolved in the material. How much of it you need is a separate question again, and the topsoil calculator handles that one.
Oregon State University Extension publication EM 9307, Herbicide-Contaminated Compost and Soil Mix (February 2021, Weston Miller and Kaci Buhl), states the problem directly: compost and soil mix products sometimes contain herbicide residue, and it gives clopyralid and aminopyralid as examples of herbicides that persist through the composting process. The route in is contaminated hay, grass clippings or manure entering the regional composting stream.
The National Pesticide Information Center, run by Oregon State under a cooperative agreement with the US EPA, names clopyralid, aminopyralid and picloram in its compost FAQ, last updated 14 August 2024. It describes the livestock step: residues pass through the animal's digestive tract unchanged and end up in urine and manure. On persistence it says only that, depending on soil conditions, clopyralid may last months to years in soil.
EM 9307 groups the crops prone to damage by plant family: beans and peas; tomatoes, peppers and potatoes; summer and winter squash; lettuce, sunflowers and dahlias; spinach, chard and beets; carrots and parsley; roses; grapes; hemp. Monocots are not affected, so turfgrass, ornamental grasses, lilies and irises are safe, and corn may take up residue without showing symptoms. Look for distorted or cupped leaves, with the damage in new growth and at shoot tips. EM 9307's rule for telling this apart from disease or a nutrient deficiency is that herbicide injury tends to show up in more than one kind of plant, and on only one part of those plants.
If contaminated material is already spread, the publication's do-nothing option is measured in years: it puts complete degradation of the herbicide at two to five years. That is the expensive outcome, and it is why the test below belongs before the truck arrives.
University of Georgia Extension Circular C 1374, published 3 August 2026, puts figures on the laboratory route for aminopyralid in soil. Chemical analysis runs $130 to $400 per sample and cannot detect concentrations below 0.2 micrograms per kilogram of soil, and the circular reports that field experiments in Florida found severe damage and yield reduction in sensitive vegetable crops below that level. NPIC makes the same point without figures: some plants are more sensitive than laboratory tests and can be damaged at levels too low for the lab to detect. EM 9307 says plainly that chemical lab testing might not indicate contamination.
The answer both reach for is a bioassay: grow a sensitive plant in the material and look at it. Two published procedures, aimed at different materials. EM 9307 tests a compost or soil mix product before you spread it. C 1374 tests soil already in the ground. The logic is the same.
C 1374 notes that green beans are more sensitive to aminopyralid than squash, which makes them the better indicator at low concentrations. EM 9307 puts the whole exercise at three to four weeks to get results, and adds the step people skip: get a sample from the vendor before you buy, then confirm that what you tested came from the same batch that gets delivered.
| Step | OSU EM 9307 (Feb 2021) | UGA C 1374 (Aug 2026) |
|---|---|---|
| Species | Garden pea | Green bean and butternut squash |
| Container | New 4-inch plastic pots | 8 oz foam cup with a ~0.5 in drainage hole, nested in a second cup |
| Replicates | 3 test pots, 3 control pots | 2 replications per sampling point, per species |
| Control | Peat-based potting mix bought without compost in it | Soil from a known-clean area |
| Material tested | Compost at 2 parts test material to 1 part potting mix | Soil collected to about 11 in deep, ~4 lb per sampling area |
| Seeds | 3 per pot, planted 1 in deep | 3 per cup, on the surface, covered with sand |
| Read the result | At three sets of leaves, 14-21 days after germination | 2-3 weeks after seeding; continue to 4 weeks if no injury shows |
No federal standard sets a maximum herbicide residue for bulk landscape topsoil or compost sold to a homeowner. The federal pesticide residue limits that do exist are food tolerances, set out in 40 CFR Part 180, Tolerances and Exemptions for Pesticide Chemical Residues in Food. They govern residues in or on food and animal feed. A pile of soil in a supplier's yard is not within that part, and nothing else fills the gap. ASTM D5268-23's list of required determinations does not include pesticide residue either.
"Screened" is not a contamination claim. Screening is a size operation: it removes whatever will not pass the mesh, which is the same family of things D5268-23 treats as deleterious material. A dissolved herbicide passes every screen ever built. No published US standard defines screened topsoil as a grade or fixes an aperture for it, so whatever screen size a yard quotes, if it quotes one at all, is that yard's own trade description rather than a figure you can look up and hold them to.
That leaves asking and testing. The first of EM 9307's five keys is to contact the vendor before buying a bulk load and ask how they handle herbicide contamination risk and whether they have reduced potential sources. Its advice on produce is conservative: if plants show herbicide injury and you do not know which herbicide caused it, do not eat the produce. If you do know the active ingredient, NPIC will take the question on 1-800-858-7378 (npic.orst.edu/faq/compost.html). Its complaint route is Oregon-specific, with the Oregon Department of Agriculture investigating pesticide complaints there and a 30-day window after damage is first noticed beyond which a complaint will be filed but may not be investigated; that clock is an Oregon figure and does not transfer to other states, where your own state pesticide regulator is the equivalent. Once you are satisfied the material is fit for purpose, the quantity side is covered by our material calculators.