Soil pH in St. Joseph, IN: Lime or Sulfur?

Typical topsoil pH in St. Joseph, IN

Typical topsoil in St. Joseph, IN is pH 6.41, already right for vegetable garden (6-7). Test before adding anything.

What St. Joseph needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, strawberries, roses, pink hydrangeas.
• Sulfur: potatoes 2.1 lb/100 sq ft over 2 applications; blueberries 3.2 lb/100 sq ft over 2 applications; azaleas and rhododendrons 2.8 lb/100 sq ft over 2 applications; blue hydrangeas 2.8 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.41, 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 248,071 surveyed acres in St. Joseph, IN, 57% are near neutral (6.5-7.3), 39% are moderately acidic (5.5-6.5), 4% are alkaline (above 7.3), 1% are strongly acidic (below 5.5). Mapped soils run from pH 4.9 to 8.1, a spread of 3.2 units across 641 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 12.4% clay and 2.71% 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. 5% of mapped components carry free carbonate (lime already in the ground).

St. Joseph against the rest of Indiana

pH 6.41 is 0.06 above the Indiana median of 6.35. 55 of 92 Indiana counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Union (6.4), Cass (6.41), Delaware (6.41), Newton (6.41), Shelby (6.41), White (6.41), Lagrange (6.42), Adams (6.44).

The range in Indiana runs from Brown at 4.97 to Hamilton at 6.74; St. Joseph sits 81% of the way up.