Soil pH in Isabella, MI: Lime or Sulfur?

Typical topsoil pH in Isabella, MI

Typical topsoil in Isabella, MI is pH 6.31, already right for vegetable garden (6-7). Test before adding anything.

What Isabella 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 6.31, 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 346,964 surveyed acres in Isabella, MI, 46% are moderately acidic (5.5-6.5), 43% are near neutral (6.5-7.3), 6% are alkaline (above 7.3), 4% are strongly acidic (below 5.5). Mapped soils run from pH 4.1 to 8, a spread of 3.9 units across 366 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 10.7% clay and 2.81% 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. 4% of mapped components carry free carbonate (lime already in the ground).

Isabella against the rest of Michigan

pH 6.31 is 0.27 above the Michigan median of 6.04. 56 of 83 Michigan counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Calhoun (6.2), Berrien (6.25), Kent (6.27), Presque Isle (6.27), Branch (6.32), Menominee (6.36), Arenac (6.37), Eaton (6.37).

The range in Michigan runs from Baraga at 4.72 to Huron at 7.03; Isabella sits 69% of the way up.