Soil pH in Washington, KS: Lime or Sulfur?

Typical topsoil pH in Washington, KS

Typical topsoil in Washington, KS is pH 6.05, already right for vegetable garden (6-7). Test before adding anything.

What Washington needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, strawberries, roses, pink hydrangeas.
• Just outside, test first: tomatoes (off by 0.2), potatoes (off by 0), azaleas and rhododendrons (off by 0).
• Sulfur: blueberries 3.4 lb/100 sq ft over 2 applications; blue hydrangeas 2.7 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.05, 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 570,344 surveyed acres in Washington, KS, 83% are moderately acidic (5.5-6.5), 13% are near neutral (6.5-7.3), 4% are alkaline (above 7.3). Mapped soils run from pH 5.5 to 7.9, a spread of 2.4 units across 199 soil components. 83% 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 27.3% clay and 2.93% 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. 4% of mapped components carry free carbonate (lime already in the ground).

Washington against the rest of Kansas

pH 6.05 is 0.52 below the Kansas median of 6.57. 1 of 105 Kansas counties have more acidic topsoil. Nationally it is level with than the US county median of 6.05.

Closest in pH within the state: Cherokee (5.95), Clay (6.05), Brown (6.06), McPherson (6.06), Crawford (6.12), Montgomery (6.12).

The range in Kansas runs from Cherokee at 5.95 to Wallace at 7.51; Washington sits 6% of the way up.