Soil pH in Decatur, KS: Lime or Sulfur?

Typical topsoil pH in Decatur, KS

Typical topsoil in Decatur, KS is pH 6.91, already right for vegetable garden (6-7). Test before adding anything.

What Decatur needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, roses.
• Just outside, test first: tomatoes (off by 0.1).
• Beds or pots instead: potatoes, strawberries, blueberries, azaleas and rhododendrons, blue hydrangeas, pink hydrangeas.

What to do next

If your test lands near 6.91, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, tomatoes, roses.

How mixed the soil is

Of the 572,105 surveyed acres in Decatur, KS, 37% are moderately acidic (5.5-6.5), 34% are alkaline (above 7.3), 29% are near neutral (6.5-7.3). Mapped soils run from pH 5.5 to 8.2, a spread of 2.7 units across 91 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 21.7% clay and 2.07% 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. 34% of mapped components carry free carbonate (lime already in the ground), enough that sulfur gets neutralised before it does much.

Decatur against the rest of Kansas

pH 6.91 is 0.34 above the Kansas median of 6.57. 71 of 105 Kansas counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Phillips (6.84), Lincoln (6.88), Smith (6.88), Gray (6.9), Mitchell (6.99), Rooks (7.05), Barber (7.06), Hodgeman (7.08).

The range in Kansas runs from Cherokee at 5.95 to Wallace at 7.51; Decatur sits 62% of the way up.