Soil pH in Smyth, VA: Lime or Sulfur?

Typical topsoil pH in Smyth, VA

Typical topsoil in Smyth, VA is pH 5.48, too acidic for vegetable garden. Expect roughly 7 lb of lime per 100 sq ft, but only after a soil test confirms it.

What Smyth needs, by plant

• Already in range: potatoes, blueberries, azaleas and rhododendrons, blue hydrangeas.
• Just outside, test first: strawberries (off by 0).
• Lime: lawn (cool-season grass) 7 lb/100 sq ft over 2 applications; vegetable garden 7 lb/100 sq ft over 2 applications; tomatoes 7 lb/100 sq ft over 2 applications; roses 7 lb/100 sq ft over 2 applications; pink hydrangeas 5.6 lb/100 sq ft over 2 applications.

What to do next

If your test confirms pH near 5.48, spread about 70 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 161,459 surveyed acres in Smyth, VA, 48% are moderately acidic (5.5-6.5), 44% are strongly acidic (below 5.5), 8% are near neutral (6.5-7.3). Mapped soils run from pH 4.2 to 7, a spread of 2.8 units across 105 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 19.4% clay and 1.41% 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.

Smyth against the rest of Virginia

pH 5.48 is 0.24 above the Virginia median of 5.24. 105 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: Salem City (5.43), Shenandoah (5.45), Charlotte (5.46), Accomack (5.47), Buchanan (5.5), Prince Edward (5.51), Bristol City (5.52), Floyd (5.54).

The range in Virginia runs from Newport News City at 4.76 to Poquoson City at 6.36; Smyth sits 45% of the way up.