Soil pH in Pawnee, OK: Lime or Sulfur?

Typical topsoil pH in Pawnee, OK

Typical topsoil in Pawnee, OK is pH 6.44, already right for vegetable garden (6-7). Test before adding anything.

What Pawnee needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, strawberries, roses, pink hydrangeas.
• Sulfur: potatoes 2.1 lb/100 sq ft over 2 applications; blueberries 3.2 lb/100 sq ft over 2 applications; azaleas and rhododendrons 2.8 lb/100 sq ft over 2 applications; blue hydrangeas 2.8 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.44, 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 311,937 surveyed acres in Pawnee, OK, 51% are near neutral (6.5-7.3), 39% are moderately acidic (5.5-6.5), 7% are alkaline (above 7.3), 3% are strongly acidic (below 5.5). Mapped soils run from pH 5 to 8.2, a spread of 3.2 units across 229 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 19.9% clay and 1.7% 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. 4% of mapped components carry free carbonate (lime already in the ground).

Pawnee against the rest of Oklahoma

pH 6.44 is 0.11 below the Oklahoma median of 6.55. 35 of 77 Oklahoma counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Stephens (6.35), Bryan (6.37), Cleveland (6.4), Johnston (6.42), Grady (6.49), Logan (6.52), Pottawatomie (6.55), Grant (6.56).

The range in Oklahoma runs from Adair at 5.12 to Beaver at 7.65; Pawnee sits 52% of the way up.