Soil pH in Humphreys, MS: Lime or Sulfur?

Typical topsoil pH in Humphreys, MS

Typical topsoil in Humphreys, MS is pH 5.14, too acidic for vegetable garden. Expect roughly 16.1 lb of lime per 100 sq ft, but only after a soil test confirms it.

What Humphreys needs, by plant

• Already in range: potatoes, blueberries, azaleas and rhododendrons, blue hydrangeas.
• Lime: lawn (cool-season grass) 16.1 lb/100 sq ft over 4 applications; vegetable garden 16.1 lb/100 sq ft over 4 applications; tomatoes 16.1 lb/100 sq ft over 4 applications; strawberries 10.4 lb/100 sq ft over 3 applications; roses 16.1 lb/100 sq ft over 4 applications; pink hydrangeas 12.7 lb/100 sq ft over 3 applications.

What to do next

If your test confirms pH near 5.14, spread about 161 lb of ground limestone per 1,000 sq ft of vegetable bed in 4 doses, ideally in fall.

How mixed the soil is

Of the 243,557 surveyed acres in Humphreys, MS, 95% are strongly acidic (below 5.5), 5% are moderately acidic (5.5-6.5). Mapped soils run from pH 5 to 7, a spread of 2 units across 62 soil components. 95% 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 44.5% clay and 1.84% organic matter, which this site treats as clay. Moving it one pH unit takes about 11.5 lb of lime or 3.4 lb of sulfur per 100 sq ft. None of the mapped components carry free carbonate.

Humphreys against the rest of Mississippi

pH 5.14 is right at the Mississippi median of 5.15. 39 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: Amite (5.12), Wayne (5.12), Lamar (5.13), Yalobusha (5.13), Lincoln (5.14), Prentiss (5.16), Jasper (5.17), Kemper (5.17).

The range in Mississippi runs from Hancock at 4.85 to Issaquena at 6.73; Humphreys sits 15% of the way up.