Soil pH in Clay, SD: Lime or Sulfur?

Typical topsoil pH in Clay, SD

Typical topsoil in Clay, SD is pH 7.07, just outside the 6-7 range for vegetable garden. Test first; it may need nothing.

What Clay needs, by plant

• Just outside, test first: lawn (cool-season grass) (off by 0.1), vegetable garden (off by 0.1), roses (off by 0.1).
• Beds or pots instead: tomatoes, potatoes, strawberries, blueberries, azaleas and rhododendrons, blue hydrangeas, pink hydrangeas.

What to do next

If your test lands near 7.07, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, roses.

How mixed the soil is

Of the 264,991 surveyed acres in Clay, SD, 60% are near neutral (6.5-7.3), 37% are alkaline (above 7.3), 4% are moderately acidic (5.5-6.5). Mapped soils run from pH 5.6 to 8.2, a spread of 2.6 units across 537 soil components. No single class covers 60% of the county, so two gardens a few miles apart here can need opposite treatments. Test your own bed.

Clay, organic matter and rates

Topsoil here averages 30.4% clay and 3.81% organic matter, which this site treats as clay. Moving it one pH unit takes about 11.5 lb of lime or 3.4 lb of sulfur per 100 sq ft. 48% of mapped components carry free carbonate (lime already in the ground), enough that sulfur gets neutralised before it does much.

Clay against the rest of South Dakota

pH 7.07 is 0.08 above the South Dakota median of 6.99. 44 of 66 South Dakota counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Perkins (7.03), Marshall (7.05), Edmunds (7.06), Harding (7.06), Faulk (7.07), Day (7.08), Roberts (7.08), Tripp (7.08).

The range in South Dakota runs from Lawrence at 6.49 to Jones at 7.47; Clay sits 59% of the way up.