Soil pH in Roanoke, VA: Lime or Sulfur?

Typical topsoil pH in Roanoke, VA

Typical topsoil in Roanoke, VA is pH 5.24, 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 Roanoke 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 5.24, 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 113,904 surveyed acres in Roanoke, VA, 91% are strongly acidic (below 5.5), 6% are near neutral (6.5-7.3), 3% are moderately acidic (5.5-6.5). Mapped soils run from pH 4.3 to 7.3, a spread of 3 units across 126 soil components. 91% 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 16.8% clay and 2.32% 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.

Roanoke against the rest of Virginia

pH 5.24 is right at the Virginia median of 5.24. 62 of 127 Virginia counties have more acidic topsoil. Nationally it is more acidic than the US county median of 6.05.

Closest in pH within the state: Brunswick (5.24), Greene (5.24), Louisa (5.24), Patrick (5.24), Lunenburg (5.25), Pulaski (5.25), Charlottesville City (5.25), Bland (5.26).

The range in Virginia runs from Newport News City at 4.76 to Poquoson City at 6.36; Roanoke sits 30% of the way up.