Soil pH in Douglas, MN: Lime or Sulfur?

Typical topsoil pH in Douglas, MN

Typical topsoil in Douglas, MN is pH 7.02, just outside the 6-7 range for vegetable garden. Test first; it may need nothing.

What Douglas needs, by plant

• Just outside, test first: lawn (cool-season grass) (off by 0), vegetable garden (off by 0), tomatoes (off by 0.2), roses (off by 0).
• Sulfur: potatoes 3.5 lb/100 sq ft over 2 applications; strawberries 2.3 lb/100 sq ft over 2 applications; blueberries 4.6 lb/100 sq ft over 3 applications; azaleas and rhododendrons 4.1 lb/100 sq ft over 3 applications; blue hydrangeas 4.1 lb/100 sq ft over 3 applications; pink hydrangeas 1.8 lb/100 sq ft.

What to do next

If your test lands near 7.02, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, tomatoes, roses.

How mixed the soil is

Of the 376,079 surveyed acres in Douglas, MN, 65% are near neutral (6.5-7.3), 23% are alkaline (above 7.3), 10% are moderately acidic (5.5-6.5), 1% are strongly acidic (below 5.5). Mapped soils run from pH 5.4 to 8.2, a spread of 2.8 units across 324 soil components. 65% of the land falls in one class, so the county figure is a fair first guess for most yards here.

Clay, organic matter and rates

Topsoil here averages 23.1% clay and 4.03% 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. 28% of mapped components carry free carbonate (lime already in the ground).

Douglas against the rest of Minnesota

pH 7.02 is 0.38 above the Minnesota median of 6.64. 62 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: Pipestone (6.86), Murray (6.89), McLeod (6.9), Martin (6.94), Lincoln (7.04), Renville (7.04), Kandiyohi (7.06), Pope (7.06).

The range in Minnesota runs from Cook at 5.21 to Swift at 7.49; Douglas sits 79% of the way up.