Soil pH in Walworth, SD: Lime or Sulfur?

Typical topsoil pH in Walworth, SD

Typical topsoil in Walworth, SD is pH 6.85, already right for vegetable garden (6-7). Test before adding anything.

What Walworth needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, roses.
• Just outside, test first: tomatoes (off by 0).
• Sulfur: potatoes 3 lb/100 sq ft over 2 applications; strawberries 1.8 lb/100 sq ft; blueberries 4.1 lb/100 sq ft over 3 applications; azaleas and rhododendrons 3.7 lb/100 sq ft over 2 applications; blue hydrangeas 3.7 lb/100 sq ft over 2 applications; pink hydrangeas 1.4 lb/100 sq ft.

What to do next

If your test lands near 6.85, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, tomatoes, roses.

How mixed the soil is

Of the 445,817 surveyed acres in Walworth, SD, 42% are moderately acidic (5.5-6.5), 38% are near neutral (6.5-7.3), 20% are alkaline (above 7.3). Mapped soils run from pH 6 to 8.8, a spread of 2.8 units across 851 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 25.9% clay and 3.46% 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. 24% of mapped components carry free carbonate (lime already in the ground).

Walworth against the rest of South Dakota

pH 6.85 is 0.14 below the South Dakota median of 6.99. 14 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: Turner (6.84), Charles Mix (6.85), Hanson (6.85), Hutchinson (6.85), Hyde (6.87), McCook (6.89), Minnehaha (6.89), Spink (6.89).

The range in South Dakota runs from Lawrence at 6.49 to Jones at 7.47; Walworth sits 37% of the way up.