Soil pH in Lake, MT: Lime or Sulfur?

Typical topsoil pH in Lake, MT

Typical topsoil in Lake, MT is pH 6.69, already right for vegetable garden (6-7). Test before adding anything.

What Lake needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, roses.
• Just outside, test first: strawberries (off by 0.2), pink hydrangeas (off by 0.2).
• Sulfur: potatoes 2.8 lb/100 sq ft over 2 applications; blueberries 3.9 lb/100 sq ft over 2 applications; azaleas and rhododendrons 3.2 lb/100 sq ft over 2 applications; blue hydrangeas 3.2 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.69, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, tomatoes, strawberries, roses, pink hydrangeas.

How mixed the soil is

Of the 785,619 surveyed acres in Lake, MT, 48% are near neutral (6.5-7.3), 19% are alkaline (above 7.3), 18% are strongly acidic (below 5.5), 16% are moderately acidic (5.5-6.5). Mapped soils run from pH 5 to 9.1, a spread of 4.1 units across 884 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 16.6% clay and 2.85% 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. 5% of mapped components carry free carbonate (lime already in the ground).

Lake against the rest of Montana

pH 6.69 is 0.61 below the Montana median of 7.3. 13 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: Sanders (6.37), Madison (6.46), Powell (6.46), Meagher (6.47), Lewis and Clark (6.78), Beaverhead (6.79), Gallatin (6.85), Jefferson (6.95).

The range in Montana runs from Flathead at 6.02 to Wheatland at 7.77; Lake sits 38% of the way up.