Soil pH in Macon, IL: Lime or Sulfur?

Typical topsoil pH in Macon, IL

Typical topsoil in Macon, IL is pH 6.44, already right for vegetable garden (6-7). Test before adding anything.

What Macon needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, strawberries, roses, pink hydrangeas.
• Sulfur: potatoes 3.1 lb/100 sq ft over 2 applications; blueberries 4.8 lb/100 sq ft over 3 applications; azaleas and rhododendrons 4.1 lb/100 sq ft over 3 applications; blue hydrangeas 4.1 lb/100 sq ft over 3 applications.

What to do next

If your test lands near 6.44, 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 359,153 surveyed acres in Macon, IL, 51% are moderately acidic (5.5-6.5), 48% are near neutral (6.5-7.3), 2% are alkaline (above 7.3). Mapped soils run from pH 5.5 to 8.2, a spread of 2.7 units across 184 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 27% clay and 4.1% 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. 2% of mapped components carry free carbonate (lime already in the ground).

Macon against the rest of Illinois

pH 6.44 is right at the Illinois median of 6.4. 61 of 102 Illinois counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Christian (6.43), Cumberland (6.43), Schuyler (6.43), Shelby (6.43), Montgomery (6.44), Wayne (6.44), Henry (6.45), Jo Daviess (6.45).

The range in Illinois runs from Pope at 5.5 to Grundy at 6.75; Macon sits 75% of the way up.