Soil pH in Kootenai, ID: Lime or Sulfur?

Typical topsoil pH in Kootenai, ID

Typical topsoil in Kootenai, ID is pH 6.44, already right for vegetable garden (6-7). Test before adding anything.

What Kootenai needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, strawberries, roses, pink hydrangeas.
• Sulfur: potatoes 1.1 lb/100 sq ft; blueberries 1.7 lb/100 sq ft; azaleas and rhododendrons 1.4 lb/100 sq ft; blue hydrangeas 1.4 lb/100 sq ft.

What to do next

If your test lands near 6.44, 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 663,239 surveyed acres in Kootenai, ID, 57% are near neutral (6.5-7.3), 42% are moderately acidic (5.5-6.5). Mapped soils run from pH 4.8 to 9.5, a spread of 4.7 units across 978 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 9.6% clay and 4.06% organic matter, which this site treats as sandy. Moving it one pH unit takes about 3 lb of lime or 1.2 lb of sulfur per 100 sq ft. None of the mapped components carry free carbonate.

Kootenai against the rest of Idaho

pH 6.44 is 0.57 below the Idaho median of 7.01. 8 of 44 Idaho counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Clearwater (6.32), Shoshone (6.32), Bonner (6.38), Fremont (6.42), Idaho (6.46), Lewis (6.46), Benewah (6.49), Camas (6.49).

The range in Idaho runs from Valley at 6.04 to Jefferson at 8.06; Kootenai sits 20% of the way up.