Soil pH in Glacier, MT: Lime or Sulfur?

Typical topsoil pH in Glacier, MT

Typical topsoil in Glacier, MT is pH 7.15, just outside the 6-7 range for vegetable garden. Test first; it may need nothing.

What Glacier needs, by plant

• Just outside, test first: lawn (cool-season grass) (off by 0.2), vegetable garden (off by 0.2), roses (off by 0.2).
• Sulfur: tomatoes 1.6 lb/100 sq ft; potatoes 3.9 lb/100 sq ft over 2 applications; strawberries 2.8 lb/100 sq ft over 2 applications; blueberries 5.1 lb/100 sq ft over 3 applications; azaleas and rhododendrons 4.4 lb/100 sq ft over 3 applications; blue hydrangeas 4.4 lb/100 sq ft over 3 applications; pink hydrangeas 2.1 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 7.15, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, roses.

How mixed the soil is

Of the 1,491,324 surveyed acres in Glacier, MT, 73% are near neutral (6.5-7.3), 23% are alkaline (above 7.3), 3% are moderately acidic (5.5-6.5), 1% are strongly acidic (below 5.5). Mapped soils run from pH 5 to 8.7, a spread of 3.7 units across 761 soil components. 73% 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 24.7% clay and 3.09% 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. 20% of mapped components carry free carbonate (lime already in the ground).

Glacier against the rest of Montana

pH 7.15 is 0.15 below the Montana median of 7.3. 18 of 56 Montana counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Lewis and Clark (6.78), Beaverhead (6.79), Gallatin (6.85), Jefferson (6.95), Hill (7.17), Phillips (7.17), Blaine (7.19), Valley (7.19).

The range in Montana runs from Flathead at 6.02 to Wheatland at 7.77; Glacier sits 65% of the way up.