Soil pH in Duplin, NC: Lime or Sulfur?

Typical topsoil pH in Duplin, NC

Typical topsoil in Duplin, NC is pH 5.06, too acidic for vegetable garden. Expect roughly 4.2 lb of lime per 100 sq ft, but only after a soil test confirms it.

What Duplin needs, by plant

• Already in range: potatoes, blueberries, azaleas and rhododendrons, blue hydrangeas.
• Lime: lawn (cool-season grass) 4.2 lb/100 sq ft; vegetable garden 4.2 lb/100 sq ft; tomatoes 4.2 lb/100 sq ft; strawberries 2.7 lb/100 sq ft; roses 4.2 lb/100 sq ft; pink hydrangeas 3.6 lb/100 sq ft.

What to do next

If your test confirms pH near 5.06, spread about 42 lb of ground limestone per 1,000 sq ft of vegetable bed, ideally in fall.

How mixed the soil is

Of the 467,112 surveyed acres in Duplin, NC, 69% are strongly acidic (below 5.5), 31% are moderately acidic (5.5-6.5). Mapped soils run from pH 4 to 8, a spread of 4 units across 74 soil components. 69% 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 8.3% clay and 2.54% organic matter, which this site treats as sandy. Moving it one pH unit takes about 3 lb of lime or 1.2 lb of sulfur per 100 sq ft. 0% of mapped components carry free carbonate (lime already in the ground).

Duplin against the rest of North Carolina

pH 5.06 is 0.1 below the North Carolina median of 5.16. 35 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: Cumberland (5.03), Avery (5.04), Clay (5.05), Washington (5.05), Mitchell (5.08), Transylvania (5.08), Watauga (5.08), Johnston (5.1).

The range in North Carolina runs from Swain at 4.56 to Davie at 5.9; Duplin sits 37% of the way up.