Soil pH in Swain, NC: Lime or Sulfur?

Typical topsoil pH in Swain, NC

Typical topsoil in Swain, NC is pH 4.56, too acidic for vegetable garden. Expect roughly 21.8 lb of lime per 100 sq ft, but only after a soil test confirms it.

What Swain needs, by plant

• Already in range: blueberries, azaleas and rhododendrons.
• Lime: lawn (cool-season grass) 21.8 lb/100 sq ft over 5 applications; vegetable garden 21.8 lb/100 sq ft over 5 applications; tomatoes 21.8 lb/100 sq ft over 5 applications; potatoes 10.4 lb/100 sq ft over 3 applications; strawberries 16.1 lb/100 sq ft over 4 applications; roses 21.8 lb/100 sq ft over 5 applications; blue hydrangeas 8 lb/100 sq ft over 2 applications; pink hydrangeas 19.6 lb/100 sq ft over 4 applications.

What to do next

If your test confirms pH near 4.56, spread about 218 lb of ground limestone per 1,000 sq ft of vegetable bed in 5 doses, ideally in fall.

How mixed the soil is

Of the 306,398 surveyed acres in Swain, NC, 96% are strongly acidic (below 5.5), 4% are moderately acidic (5.5-6.5). Mapped soils run from pH 3.3 to 6.5, a spread of 3.2 units across 602 soil components. 96% of the land falls in one class, so the county figure is a fair first guess for most yards here.

Clay, organic matter and rates

Topsoil here averages 15.1% clay and 5.42% organic matter, which this site treats as clay. At 5.42% organic matter the soil buffers like a heavier one, which pushes it into the clay bracket. Moving it one pH unit takes about 11.5 lb of lime or 3.4 lb of sulfur per 100 sq ft. None of the mapped components carry free carbonate.

Swain against the rest of North Carolina

pH 4.56 is 0.6 below the North Carolina median of 5.16. 0 of 100 North Carolina counties have more acidic topsoil. Nationally it is more acidic than the US county median of 6.05.

Closest in pH within the state: Jones (4.73), Graham (4.75), Pitt (4.8), Currituck (4.81).