Soil pH in Clinton, IA: Lime or Sulfur?

Typical topsoil pH in Clinton, IA

Typical topsoil in Clinton, IA is pH 6.34, already right for vegetable garden (6-7). Test before adding anything.

What Clinton needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, strawberries, roses, pink hydrangeas.
• Sulfur: potatoes 1.8 lb/100 sq ft; blueberries 3 lb/100 sq ft over 2 applications; azaleas and rhododendrons 2.5 lb/100 sq ft over 2 applications; blue hydrangeas 2.5 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.34, 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 439,337 surveyed acres in Clinton, IA, 61% are moderately acidic (5.5-6.5), 39% are near neutral (6.5-7.3), 1% are alkaline (above 7.3). Mapped soils run from pH 4.2 to 7.9, a spread of 3.7 units across 447 soil components. 61% 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 22.9% clay and 3.13% 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. 1% of mapped components carry free carbonate (lime already in the ground).

Clinton against the rest of Iowa

pH 6.34 is right at the Iowa median of 6.36. 40 of 99 Iowa counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Muscatine (6.33), Scott (6.33), Tama (6.33), Carroll (6.34), Delaware (6.34), Des Moines (6.34), Linn (6.34), Benton (6.35).

The range in Iowa runs from Van Buren at 6.02 to Monona at 7.11; Clinton sits 29% of the way up.