Soil pH in Clay, MN: Lime or Sulfur?

Typical topsoil pH in Clay, MN

Typical topsoil in Clay, MN is pH 7.43 and calcareous, so sulfur won't lower it for long. For vegetable garden, choose alkaline-tolerant varieties and add compost rather than fighting the soil.

What Clay needs, by plant

• Beds or pots instead: lawn (cool-season grass), vegetable garden, tomatoes, potatoes, strawberries, roses, blueberries, azaleas and rhododendrons, blue hydrangeas, pink hydrangeas.

What to do next

If your test confirms pH near 7.43, consider raised beds for anything acid-loving; with 58% of soils here carrying free lime, sulfur will not hold.

How mixed the soil is

Of the 652,606 surveyed acres in Clay, MN, 56% are alkaline (above 7.3), 42% are near neutral (6.5-7.3), 2% are moderately acidic (5.5-6.5). Mapped soils run from pH 5.4 to 8.2, a spread of 2.8 units across 550 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 26.2% clay and 4.4% 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. 58% of mapped components carry free carbonate (lime already in the ground), enough that sulfur gets neutralised before it does much.

Clay against the rest of Minnesota

pH 7.43 is 0.79 above the Minnesota median of 6.64. 84 of 87 Minnesota counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Chippewa (7.37), Kittson (7.37), Marshall (7.37), Polk (7.4), Norman (7.49), Swift (7.49).

The range in Minnesota runs from Cook at 5.21 to Swift at 7.49; Clay sits 97% of the way up.