Soil pH in Washington, MS: Lime or Sulfur?

Typical topsoil pH in Washington, MS

Typical topsoil in Washington, MS is pH 6.34, already right for vegetable garden (6-7). Test before adding anything.

What Washington needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, strawberries, roses, pink hydrangeas.
• Sulfur: potatoes 2.7 lb/100 sq ft over 2 applications; blueberries 4.4 lb/100 sq ft over 3 applications; azaleas and rhododendrons 3.7 lb/100 sq ft over 2 applications; blue hydrangeas 3.7 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.34, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, tomatoes, strawberries, roses, pink hydrangeas.

How mixed the soil is

Of the 437,193 surveyed acres in Washington, MS, 66% are near neutral (6.5-7.3), 23% are strongly acidic (below 5.5), 11% are moderately acidic (5.5-6.5). Mapped soils run from pH 5 to 7.3, a spread of 2.3 units across 139 soil components. 66% 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 46.7% clay and 1.83% 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. 1% of mapped components carry free carbonate (lime already in the ground).

Washington against the rest of Mississippi

pH 6.34 is 1.19 above the Mississippi median of 5.15. 80 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: Tunica (5.95), Coahoma (6.1), Bolivar (6.28), Sharkey (6.33), Issaquena (6.73).

The range in Mississippi runs from Hancock at 4.85 to Issaquena at 6.73; Washington sits 79% of the way up.