Soil pH in Baltimore City, MD: Lime or Sulfur?

Typical topsoil pH in Baltimore City, MD

Typical topsoil in Baltimore City, MD is pH 5.03, too acidic for vegetable garden. Expect roughly 10.5 lb of lime per 100 sq ft, but only after a soil test confirms it.

What Baltimore City needs, by plant

• Already in range: potatoes, blueberries, azaleas and rhododendrons, blue hydrangeas.
• Lime: lawn (cool-season grass) 10.5 lb/100 sq ft over 3 applications; vegetable garden 10.5 lb/100 sq ft over 3 applications; tomatoes 10.5 lb/100 sq ft over 3 applications; strawberries 7 lb/100 sq ft over 2 applications; roses 10.5 lb/100 sq ft over 3 applications; pink hydrangeas 8.4 lb/100 sq ft over 2 applications.

What to do next

If your test confirms pH near 5.03, spread about 105 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 24,777 surveyed acres in Baltimore City, MD, 70% are strongly acidic (below 5.5), 29% are moderately acidic (5.5-6.5). Mapped soils run from pH 4.3 to 6.5, a spread of 2.2 units across 191 soil components. 70% 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 16.9% clay and 1.77% 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.

Baltimore City against the rest of Maryland

pH 5.03 is 0.46 below the Maryland median of 5.49. 4 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), Prince George's (4.75), Garrett (4.99), Allegany (5), Anne Arundel (5.05), St. Mary's (5.2), Calvert (5.31), Harford (5.33).

The range in Maryland runs from Charles at 4.47 to Washington at 6.01; Baltimore City sits 36% of the way up.