Soil pH in Carlton, MN: Lime or Sulfur?

Typical topsoil pH in Carlton, MN

Typical topsoil in Carlton, MN is pH 5.59, too acidic for vegetable garden. Expect roughly 6.3 lb of lime per 100 sq ft, but only after a soil test confirms it.

What Carlton needs, by plant

• Already in range: potatoes, strawberries, azaleas and rhododendrons.
• Just outside, test first: blueberries (off by 0.1), blue hydrangeas (off by 0.1).
• Lime: lawn (cool-season grass) 6.3 lb/100 sq ft over 2 applications; vegetable garden 6.3 lb/100 sq ft over 2 applications; tomatoes 6.3 lb/100 sq ft over 2 applications; roses 6.3 lb/100 sq ft over 2 applications; pink hydrangeas 4.9 lb/100 sq ft.

What to do next

If your test confirms pH near 5.59, spread about 63 lb of ground limestone per 1,000 sq ft of vegetable bed in 2 doses, ideally in fall.

How mixed the soil is

Of the 385,501 surveyed acres in Carlton, MN, 47% are strongly acidic (below 5.5), 44% are moderately acidic (5.5-6.5), 5% are near neutral (6.5-7.3), 4% are alkaline (above 7.3). Mapped soils run from pH 4.5 to 7.8, a spread of 3.3 units across 121 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 14.8% clay and 3.15% 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).

Carlton against the rest of Minnesota

pH 5.59 is 1.05 below the Minnesota median of 6.64. 4 of 87 Minnesota counties have more acidic topsoil. Nationally it is more acidic than the US county median of 6.05.

Closest in pH within the state: Cook (5.21), Crow Wing (5.35), Lake (5.36), St. Louis (5.5), Pine (5.84), Chisago (5.87), Kanabec (5.91), Isanti (5.92).

The range in Minnesota runs from Cook at 5.21 to Swift at 7.49; Carlton sits 17% of the way up.