Soil pH in Coahoma, MS: Lime or Sulfur?

Typical topsoil pH in Coahoma, MS

Typical topsoil in Coahoma, MS is pH 6.1, already right for vegetable garden (6-7). Test before adding anything.

What Coahoma needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, strawberries, roses, pink hydrangeas.
• Just outside, test first: tomatoes (off by 0.1), potatoes (off by 0.1), azaleas and rhododendrons (off by 0.1).
• Sulfur: blueberries 3.7 lb/100 sq ft over 2 applications; blue hydrangeas 2.7 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.1, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, tomatoes, potatoes, strawberries, roses, azaleas and rhododendrons, pink hydrangeas.

How mixed the soil is

Of the 320,619 surveyed acres in Coahoma, MS, 51% are near neutral (6.5-7.3), 39% are strongly acidic (below 5.5), 10% are moderately acidic (5.5-6.5). Mapped soils run from pH 5 to 7.3, a spread of 2.3 units across 116 soil components. No single class covers 60% of the county, so two gardens a few miles apart here can need opposite treatments. Test your own bed.

Clay, organic matter and rates

Topsoil here averages 37.2% clay and 1.53% 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. 3% of mapped components carry free carbonate (lime already in the ground).

Coahoma against the rest of Mississippi

pH 6.1 is 0.95 above the Mississippi median of 5.15. 77 of 82 Mississippi counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Clay (5.76), Yazoo (5.79), Warren (5.92), Tunica (5.95), Bolivar (6.28), Sharkey (6.33), Washington (6.34), Issaquena (6.73).

The range in Mississippi runs from Hancock at 4.85 to Issaquena at 6.73; Coahoma sits 66% of the way up.