Soil pH in Clay, MS: Lime or Sulfur?

Typical topsoil pH in Clay, MS

Typical topsoil in Clay, MS is pH 5.76, just outside the 6-7 range for vegetable garden. Test first; it may need nothing.

What Clay needs, by plant

• Already in range: potatoes, strawberries, azaleas and rhododendrons.
• Just outside, test first: lawn (cool-season grass) (off by 0.2), vegetable garden (off by 0.2), roses (off by 0.2), pink hydrangeas (off by 0.2).
• Lime: tomatoes 4.9 lb/100 sq ft.
• Sulfur: blueberries 1.8 lb/100 sq ft; blue hydrangeas 1.2 lb/100 sq ft.

What to do next

If your test lands near 5.76, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, potatoes, strawberries, roses, azaleas and rhododendrons, pink hydrangeas.

How mixed the soil is

Of the 258,085 surveyed acres in Clay, MS, 62% are strongly acidic (below 5.5), 21% are alkaline (above 7.3), 11% are near neutral (6.5-7.3), 6% are moderately acidic (5.5-6.5). Mapped soils run from pH 4.4 to 8.1, a spread of 3.7 units across 135 soil components. 62% 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 23.2% clay and 2.1% 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. 17% of mapped components carry free carbonate (lime already in the ground).

Clay against the rest of Mississippi

pH 5.76 is 0.61 above the Mississippi median of 5.15. 73 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: Adams (5.68), Lowndes (5.74), Noxubee (5.74), Sunflower (5.75), Yazoo (5.79), Warren (5.92), Tunica (5.95), Coahoma (6.1).

The range in Mississippi runs from Hancock at 4.85 to Issaquena at 6.73; Clay sits 48% of the way up.