Soil pH in Prairie, MT: Lime or Sulfur?

Typical topsoil pH in Prairie, MT

Typical topsoil in Prairie, MT is pH 7.7 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 Prairie 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 7.7, consider raised beds for anything acid-loving; with 64% of soils here carrying free lime, sulfur will not hold.

How mixed the soil is

Of the 1,007,260 surveyed acres in Prairie, MT, 78% are alkaline (above 7.3), 22% are near neutral (6.5-7.3). Mapped soils run from pH 5.5 to 8.8, a spread of 3.3 units across 798 soil components. 78% 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 22.4% clay and 1.85% 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. 64% of mapped components carry free carbonate (lime already in the ground), enough that sulfur gets neutralised before it does much.

Prairie against the rest of Montana

pH 7.7 is 0.4 above the Montana median of 7.3. 53 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: Custer (7.59), Garfield (7.6), Golden Valley (7.66), Musselshell (7.67), Dawson (7.71), Wheatland (7.77).

The range in Montana runs from Flathead at 6.02 to Wheatland at 7.77; Prairie sits 96% of the way up.