Soil pH in Chouteau, MT: Lime or Sulfur?

Typical topsoil pH in Chouteau, MT

Typical topsoil in Chouteau, MT is pH 7.24, just outside the 6-7 range for vegetable garden. Test first; it may need nothing.

What Chouteau 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 2.4 lb/100 sq ft over 2 applications; potatoes 5.8 lb/100 sq ft over 3 applications; strawberries 4.1 lb/100 sq ft over 3 applications; blueberries 7.5 lb/100 sq ft over 4 applications; azaleas and rhododendrons 6.8 lb/100 sq ft over 4 applications; blue hydrangeas 6.8 lb/100 sq ft over 4 applications; pink hydrangeas 3.4 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 7.24, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, roses.

How mixed the soil is

Of the 2,420,600 surveyed acres in Chouteau, MT, 71% are near neutral (6.5-7.3), 28% are alkaline (above 7.3), 1% are moderately acidic (5.5-6.5). Mapped soils run from pH 5.2 to 9, a spread of 3.8 units across 1,246 soil components. 71% 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 28.1% clay and 2.13% organic matter, which this site treats as clay. Moving it one pH unit takes about 11.5 lb of lime or 3.4 lb of sulfur per 100 sq ft. 23% of mapped components carry free carbonate (lime already in the ground).

Chouteau against the rest of Montana

pH 7.24 is 0.06 below the Montana median of 7.3. 23 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: Hill (7.17), Phillips (7.17), Blaine (7.19), Valley (7.19), Sweet Grass (7.25), Cascade (7.27), Daniels (7.28), Fergus (7.28).

The range in Montana runs from Flathead at 6.02 to Wheatland at 7.77; Chouteau sits 70% of the way up.