Soil pH in Richmond, NC: Lime or Sulfur?

Typical topsoil pH in Richmond, NC

Typical topsoil in Richmond, NC is pH 5.23, too acidic for vegetable garden. Expect roughly 9.1 lb of lime per 100 sq ft, but only after a soil test confirms it.

What Richmond needs, by plant

• Already in range: potatoes, blueberries, azaleas and rhododendrons, blue hydrangeas.
• Lime: lawn (cool-season grass) 9.1 lb/100 sq ft over 2 applications; vegetable garden 9.1 lb/100 sq ft over 2 applications; tomatoes 9.1 lb/100 sq ft over 2 applications; strawberries 5.6 lb/100 sq ft over 2 applications; roses 9.1 lb/100 sq ft over 2 applications; pink hydrangeas 7 lb/100 sq ft over 2 applications.

What to do next

If your test confirms pH near 5.23, spread about 91 lb of ground limestone per 1,000 sq ft of vegetable bed in 2 doses, ideally in fall.

How mixed the soil is

Of the 275,299 surveyed acres in Richmond, NC, 60% are strongly acidic (below 5.5), 39% are moderately acidic (5.5-6.5), 1% are near neutral (6.5-7.3). Mapped soils run from pH 4.5 to 6.5, a spread of 2 units across 128 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 10.2% clay and 1.85% 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. None of the mapped components carry free carbonate.

Richmond against the rest of North Carolina

pH 5.23 is 0.07 above the North Carolina median of 5.16. 55 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: Chatham (5.21), Carteret (5.22), Moore (5.22), New Hanover (5.23), Caldwell (5.24), Montgomery (5.24), Henderson (5.25), Buncombe (5.26).

The range in North Carolina runs from Swain at 4.56 to Davie at 5.9; Richmond sits 50% of the way up.