Soil pH in Riley, KS: Lime or Sulfur?

Typical topsoil pH in Riley, KS

Typical topsoil in Riley, KS is pH 6.68, already right for vegetable garden (6-7). Test before adding anything.

What Riley needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, roses.
• Just outside, test first: strawberries (off by 0.2), pink hydrangeas (off by 0.2).
• Sulfur: potatoes 4.1 lb/100 sq ft over 3 applications; blueberries 5.8 lb/100 sq ft over 3 applications; azaleas and rhododendrons 4.8 lb/100 sq ft over 3 applications; blue hydrangeas 4.8 lb/100 sq ft over 3 applications.

What to do next

If your test lands near 6.68, 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 383,883 surveyed acres in Riley, KS, 37% are moderately acidic (5.5-6.5), 33% are near neutral (6.5-7.3), 30% are alkaline (above 7.3). Mapped soils run from pH 5.6 to 7.9, a spread of 2.3 units across 450 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 32.1% clay and 3.01% 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. 30% of mapped components carry free carbonate (lime already in the ground).

Riley against the rest of Kansas

pH 6.68 is 0.11 above the Kansas median of 6.57. 60 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: Harper (6.64), Chase (6.65), Kiowa (6.65), Ford (6.68), Wabaunsee (6.68), Norton (6.77), Rush (6.8), Jewell (6.83).

The range in Kansas runs from Cherokee at 5.95 to Wallace at 7.51; Riley sits 47% of the way up.