Soil pH in Audrain, MO: Lime or Sulfur?

Typical topsoil pH in Audrain, MO

Typical topsoil in Audrain, MO is pH 6.51, already right for vegetable garden (6-7). Test before adding anything.

What Audrain needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, roses.
• Just outside, test first: strawberries (off by 0), pink hydrangeas (off by 0).
• Sulfur: potatoes 2.3 lb/100 sq ft over 2 applications; blueberries 3.5 lb/100 sq ft over 2 applications; azaleas and rhododendrons 3 lb/100 sq ft over 2 applications; blue hydrangeas 3 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.51, 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 443,648 surveyed acres in Audrain, MO, 80% are near neutral (6.5-7.3), 19% are moderately acidic (5.5-6.5), 1% are strongly acidic (below 5.5). Mapped soils run from pH 5 to 7.7, a spread of 2.7 units across 109 soil components. 80% 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 19.9% clay and 2.14% 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. 0% of mapped components carry free carbonate (lime already in the ground).

Audrain against the rest of Missouri

pH 6.51 is 0.38 above the Missouri median of 6.13. 102 of 114 Missouri counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Carroll (6.49), Daviess (6.49), Clay (6.5), Platte (6.5), Mercer (6.51), Shelby (6.51), Buchanan (6.52), Linn (6.52).

The range in Missouri runs from Carter at 5.08 to Knox at 6.71; Audrain sits 88% of the way up.