Soil pH in Clearwater, ID: Lime or Sulfur?

Typical topsoil pH in Clearwater, ID

Typical topsoil in Clearwater, ID is pH 6.32, already right for vegetable garden (6-7). Test before adding anything.

What Clearwater needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, strawberries, roses, pink hydrangeas.
• Sulfur: potatoes 1.8 lb/100 sq ft; blueberries 3 lb/100 sq ft over 2 applications; azaleas and rhododendrons 2.5 lb/100 sq ft over 2 applications; blue hydrangeas 2.5 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.32, 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 775,575 surveyed acres in Clearwater, ID, 51% are near neutral (6.5-7.3), 46% are moderately acidic (5.5-6.5), 3% are strongly acidic (below 5.5). Mapped soils run from pH 4.3 to 7, a spread of 2.7 units across 433 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 10.9% clay and 4.1% 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. None of the mapped components carry free carbonate.

Clearwater against the rest of Idaho

pH 6.32 is 0.69 below the Idaho median of 7.01. 4 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: Valley (6.04), Latah (6.18), Boise (6.25), Boundary (6.29), Shoshone (6.32), Bonner (6.38), Fremont (6.42), Kootenai (6.44).

The range in Idaho runs from Valley at 6.04 to Jefferson at 8.06; Clearwater sits 14% of the way up.