Soil pH in Oconto, WI: Lime or Sulfur?

Typical topsoil pH in Oconto, WI

Typical topsoil in Oconto, WI is pH 6.06, already right for vegetable garden (6-7). Test before adding anything.

What Oconto needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, strawberries, roses, pink hydrangeas.
• Just outside, test first: tomatoes (off by 0.1), potatoes (off by 0.1), azaleas and rhododendrons (off by 0.1).
• Sulfur: blueberries 1.3 lb/100 sq ft; blue hydrangeas 1 lb/100 sq ft.

What to do next

If your test lands near 6.06, 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 593,686 surveyed acres in Oconto, WI, 50% are moderately acidic (5.5-6.5), 39% are near neutral (6.5-7.3), 11% are strongly acidic (below 5.5). Mapped soils run from pH 3.9 to 7.5, a spread of 3.6 units across 354 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 7.2% clay and 3.07% organic matter, which this site treats as sandy. Moving it one pH unit takes about 3 lb of lime or 1.2 lb of sulfur per 100 sq ft. 3% of mapped components carry free carbonate (lime already in the ground).

Oconto against the rest of Wisconsin

pH 6.06 is right at the Wisconsin median of 6.08. 32 of 72 Wisconsin counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Barron (5.9), Shawano (5.98), Trempealeau (6), Dunn (6.06), St. Croix (6.06), Buffalo (6.08), Waupaca (6.09), La Crosse (6.12).

The range in Wisconsin runs from Iron at 5.16 to Washington at 6.88; Oconto sits 52% of the way up.