Soil pH in Roseau, MN: Lime or Sulfur?

Typical topsoil pH in Roseau, MN

Typical topsoil in Roseau, MN is pH 7.12, just outside the 6-7 range for vegetable garden. Test first; it may need nothing.

What Roseau needs, by plant

• Just outside, test first: lawn (cool-season grass) (off by 0.1), vegetable garden (off by 0.1), roses (off by 0.1).
• Beds or pots instead: tomatoes, potatoes, strawberries, blueberries, azaleas and rhododendrons, blue hydrangeas, pink hydrangeas.

What to do next

If your test lands near 7.12, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, roses.

How mixed the soil is

Of the 939,859 surveyed acres in Roseau, MN, 46% are alkaline (above 7.3), 42% are near neutral (6.5-7.3), 11% are moderately acidic (5.5-6.5), 1% are strongly acidic (below 5.5). Mapped soils run from pH 5.3 to 8, a spread of 2.7 units across 671 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 15.1% clay and 5.05% organic matter, which this site treats as clay. At 5.05% organic matter the soil buffers like a heavier one, which pushes it into the clay bracket. Moving it one pH unit takes about 11.5 lb of lime or 3.4 lb of sulfur per 100 sq ft. 65% of mapped components carry free carbonate (lime already in the ground), enough that sulfur gets neutralised before it does much.

Roseau against the rest of Minnesota

pH 7.12 is 0.48 above the Minnesota median of 6.64. 69 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: Kandiyohi (7.06), Pope (7.06), Mahnomen (7.07), Redwood (7.07), Lyon (7.15), Yellow Medicine (7.17), Grant (7.19), Pennington (7.19).

The range in Minnesota runs from Cook at 5.21 to Swift at 7.49; Roseau sits 84% of the way up.