Soil pH in DeKalb, MO: Lime or Sulfur?

Typical topsoil pH in DeKalb, MO

Typical topsoil in DeKalb, MO is pH 6.21, already right for vegetable garden (6-7). Test before adding anything.

What DeKalb needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, strawberries, roses, pink hydrangeas.
• Just outside, test first: potatoes (off by 0.2), azaleas and rhododendrons (off by 0.2).
• Sulfur: blueberries 4.1 lb/100 sq ft over 3 applications; blue hydrangeas 3.4 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.21, 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 270,142 surveyed acres in DeKalb, MO, 67% are moderately acidic (5.5-6.5), 27% are near neutral (6.5-7.3), 6% are strongly acidic (below 5.5). Mapped soils run from pH 4.9 to 7.4, a spread of 2.5 units across 152 soil components. 67% 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 30.3% clay and 3.12% 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.

DeKalb against the rest of Missouri

pH 6.21 is 0.08 above the Missouri median of 6.13. 63 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: Howard (6.16), Pike (6.17), Taney (6.18), Lincoln (6.19), Pemiscot (6.21), Mississippi (6.22), New Madrid (6.22), Johnson (6.24).

The range in Missouri runs from Carter at 5.08 to Knox at 6.71; DeKalb sits 69% of the way up.