Soil pH in Prince George's, MD: Lime or Sulfur?

Typical topsoil pH in Prince George's, MD

Typical topsoil in Prince George's, MD is pH 4.75, too acidic for vegetable garden. Expect roughly 12.6 lb of lime per 100 sq ft, but only after a soil test confirms it.

What Prince George's needs, by plant

• Already in range: blueberries, azaleas and rhododendrons.
• Lime: lawn (cool-season grass) 12.6 lb/100 sq ft over 3 applications; vegetable garden 12.6 lb/100 sq ft over 3 applications; tomatoes 12.6 lb/100 sq ft over 3 applications; potatoes 5.6 lb/100 sq ft over 2 applications; strawberries 9.1 lb/100 sq ft over 2 applications; roses 12.6 lb/100 sq ft over 3 applications; blue hydrangeas 3.5 lb/100 sq ft; pink hydrangeas 10.5 lb/100 sq ft over 3 applications.

What to do next

If your test confirms pH near 4.75, spread about 126 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 242,949 surveyed acres in Prince George's, MD, 90% are strongly acidic (below 5.5), 8% are moderately acidic (5.5-6.5), 2% are near neutral (6.5-7.3). Mapped soils run from pH 3.6 to 7, a spread of 3.4 units across 449 soil components. 90% 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 11.8% clay and 3.49% 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.

Prince George's against the rest of Maryland

pH 4.75 is 0.74 below the Maryland median of 5.49. 1 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: Charles (4.47), Garrett (4.99), Allegany (5), Baltimore City (5.03), Anne Arundel (5.05).

The range in Maryland runs from Charles at 4.47 to Washington at 6.01; Prince George's sits 18% of the way up.