Soil pH in Sully, SD: Lime or Sulfur?

Typical topsoil pH in Sully, SD

Typical topsoil in Sully, SD is pH 6.64, already right for vegetable garden (6-7). Test before adding anything.

What Sully needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, roses.
• Just outside, test first: strawberries (off by 0.1), pink hydrangeas (off by 0.1).
• Sulfur: potatoes 2.5 lb/100 sq ft over 2 applications; blueberries 3.7 lb/100 sq ft over 2 applications; azaleas and rhododendrons 3.2 lb/100 sq ft over 2 applications; blue hydrangeas 3.2 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.64, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, tomatoes, strawberries, roses, pink hydrangeas.

How mixed the soil is

Of the 638,988 surveyed acres in Sully, SD, 52% are moderately acidic (5.5-6.5), 40% are near neutral (6.5-7.3), 9% are alkaline (above 7.3). Mapped soils run from pH 6 to 8.8, a spread of 2.8 units across 364 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 24.1% clay and 3.31% organic matter, which this site treats as loam. Moving it one pH unit takes about 7 lb of lime or 2.3 lb of sulfur per 100 sq ft. 15% of mapped components carry free carbonate (lime already in the ground).

Sully against the rest of South Dakota

pH 6.64 is 0.35 below the South Dakota median of 6.99. 1 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: Lawrence (6.49), Lake (6.71), Douglas (6.76), Lincoln (6.76), Moody (6.78).

The range in South Dakota runs from Lawrence at 6.49 to Jones at 7.47; Sully sits 15% of the way up.