Soil pH in Charles, MD: Lime or Sulfur?

Typical topsoil pH in Charles, MD

Typical topsoil in Charles, MD is pH 4.47, too acidic for vegetable garden. Expect roughly 14 lb of lime per 100 sq ft, but only after a soil test confirms it.

What Charles needs, by plant

• Just outside, test first: blueberries (off by 0), azaleas and rhododendrons (off by 0).
• Lime: lawn (cool-season grass) 14 lb/100 sq ft over 3 applications; vegetable garden 14 lb/100 sq ft over 3 applications; tomatoes 14 lb/100 sq ft over 3 applications; potatoes 7 lb/100 sq ft over 2 applications; strawberries 10.5 lb/100 sq ft over 3 applications; roses 14 lb/100 sq ft over 3 applications; blue hydrangeas 5.6 lb/100 sq ft over 2 applications; pink hydrangeas 12.6 lb/100 sq ft over 3 applications.

What to do next

If your test confirms pH near 4.47, spread about 140 lb of ground limestone per 1,000 sq ft of vegetable bed in 3 doses, ideally in fall.

How mixed the soil is

Of the 285,636 surveyed acres in Charles, MD, 96% are strongly acidic (below 5.5), 3% are moderately acidic (5.5-6.5), 1% are near neutral (6.5-7.3). Mapped soils run from pH 3.6 to 6.5, a spread of 2.9 units across 237 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 12.1% clay and 3.9% 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.

Charles against the rest of Maryland

pH 4.47 is 1.02 below the Maryland median of 5.49. 0 of 24 Maryland counties have more acidic topsoil. Nationally it is more acidic than the US county median of 6.05.

Closest in pH within the state: Prince George's (4.75), Garrett (4.99), Allegany (5), Baltimore City (5.03).