Soil pH in Union, IL: Lime or Sulfur?

Typical topsoil pH in Union, IL

Typical topsoil in Union, IL is pH 6.02, already right for vegetable garden (6-7). Test before adding anything.

What Union 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 2.3 lb/100 sq ft over 2 applications; blue hydrangeas 1.8 lb/100 sq ft.

What to do next

If your test lands near 6.02, 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 238,928 surveyed acres in Union, IL, 68% are moderately acidic (5.5-6.5), 26% are near neutral (6.5-7.3), 6% are strongly acidic (below 5.5). Mapped soils run from pH 4.8 to 7.3, a spread of 2.5 units across 119 soil components. 68% 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 21.4% clay and 1.77% 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).

Union against the rest of Illinois

pH 6.02 is 0.38 below the Illinois median of 6.4. 5 of 102 Illinois counties have more acidic topsoil. Nationally it is more acidic than the US county median of 6.05.

Closest in pH within the state: Hardin (5.65), Massac (5.81), Williamson (5.92), Pulaski (6.02), Jefferson (6.03), Saline (6.11), Hamilton (6.13), Franklin (6.14).

The range in Illinois runs from Pope at 5.5 to Grundy at 6.75; Union sits 42% of the way up.