Soil pH in Union, MS: Lime or Sulfur?

Typical topsoil pH in Union, MS

Typical topsoil in Union, MS is pH 5.18, 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 Union 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 7.7 lb/100 sq ft over 2 applications.

What to do next

If your test confirms pH near 5.18, 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 252,890 surveyed acres in Union, MS, 87% are strongly acidic (below 5.5), 12% are moderately acidic (5.5-6.5), 1% are near neutral (6.5-7.3). Mapped soils run from pH 4.5 to 7.5, a spread of 3 units across 86 soil components. 87% 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 14.4% clay and 1.52% 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.

Union against the rest of Mississippi

pH 5.18 is right at the Mississippi median of 5.15. 44 of 82 Mississippi counties have more acidic topsoil. Nationally it is more acidic than the US county median of 6.05.

Closest in pH within the state: Jasper (5.17), Kemper (5.17), Marshall (5.18), Panola (5.18), Benton (5.21), Copiah (5.21), Franklin (5.21), Choctaw (5.22).

The range in Mississippi runs from Hancock at 4.85 to Issaquena at 6.73; Union sits 18% of the way up.