Sandy Loam Soil

What makes a soil sandy loam

Sandy loam is mostly sand with just enough fines to behave like a loam. USDA defines it as 7 to under 20% clay with more than 52% sand (or less than 7% clay with under 50% silt), in both cases with silt plus twice the clay at 30 or more.^[1] On the triangle: (7 ≤ clay < 20 and sand > 52 and silt + 2 × clay ≥ 30) or (clay < 7 and silt < 50 and silt + 2 × clay ≥ 30).

In the hand it feels gritty and forms a weak ball that will not ribbon much past an inch.^[3]

That makes it the forgiving middle of the sandy group: a median 1.6 inches of water per foot (nearly double pure sand) and 1.5% organic matter, with 69.5% of its acres well drained and only 6.1% poorly drained. It warms early, works easily and still holds a useful water reserve.^[2][4][5]

Coarse, fine and very fine sandy loam

Which sand grade dominates earns a modifier inside the class. Coarse sandy loam is a total of 25% or more very coarse and coarse sand; fine sandy loam is 30% or more fine sand with less than 30% very fine; and very fine sandy loam is 30% or more very fine sand with a total of less than 15% very coarse, coarse and medium sand.^[1] Coarser grades drain faster and hold less water; the finer ones hold a little more and are easier to seal.

What sandy loam is good for

Quite a lot. The University of Georgia notes that sandy-loam soils, well supplied with organic matter, are easily worked and quite productive, with the caveat that improving any soil takes several years.^[6] The survey bears that out: 38% of rated sandy-loam acres are cultivable (Classes I–IV) and 12% is prime farmland.

Root crops do well in it: University of Minnesota Extension calls a light sandy loam good soil for growing well-shaped roots.^[7] Which root crops suit sandy ground, and how to keep carrots from forking, is on plants for sandy soil.

Strawberries grow best in loamy or sandy soils; heavy clay reduces their growth and vigor and brings more disease, unless it is well drained. Utah State recommends incorporating 2 to 3 inches of compost to a depth of at least 12 inches before planting, raising beds on heavy ground to improve drainage, and watching salinity, since strawberries are highly salt-sensitive (above 1.8 dS/m causes stunting and leaf scorch).^[8]

Is sandy loam the same as topsoil? Can you buy it?

Sandy loam is a texture, not a product grade; topsoil is the surface layer of a soil and can be any texture. But sandy loam is the texture to look for when you buy topsoil in bulk. UConn names sandy loams and fine sandy loams as the ideal purchased topsoil (loams and silt loams are acceptable), and says to avoid sands, which hold too little water and nutrients, and clays, sandy clays, silty clays and silts, which are hard to work and drain poorly.^[9] Aim for 2 to 10% organic matter, inspect the stockpile for trash and rocks over 3 inches, and get a soil test, because few sellers test their product. This guidance is written for bulk topsoil sold by the cubic yard, usually with a 3-to-6-yard minimum delivery.^[9]

Where sandy loam is found in the US

Sandy loam is one of the most extensive US surface textures, led by Texas, California and Nevada. Its most widespread series are Smithdale (Mississippi) and the red Piedmont soil Cecil (Georgia).^[2]

Most widespread sandy loam soil series

Lawns, top-dressing and a warning on “sandy loam” fixes

Sandy loam spreads evenly and drains, which makes it a popular lawn top-dressing. The rule, though, is to match the top-dressing to the native soil and apply it thinly; the rates are on soil amendments.

Don’t try to make a sandy loam by working sand into clay. In the wrong proportions it sets denser, not looser, and a coarse layer under finer soil actually slows drainage. Mix in organic matter instead, as the clay page explains.^[10][11]

Frequently asked questions

What is sandy loam?

A mostly-sand soil with 7–20% clay and over 52% sand: gritty, fast-warming and easy to work, but holding more water than pure sand.^[1][5][2]

Is sandy loam the same as topsoil?

No. Sandy loam is a texture; topsoil is the surface layer of a soil. But sandy loam is the texture UConn recommends when buying topsoil.^[9]

Is sandy loam good for strawberries?

Yes. Strawberries grow best in loamy or sandy soils. Work 2–3 inches of compost into the top foot first, and watch salinity.^[8]