Soil pH in Fremont, ID: Lime or Sulfur?

Typical topsoil pH in Fremont, ID

Typical topsoil in Fremont, ID is pH 6.42, already right for vegetable garden (6-7). Test before adding anything.

What Fremont needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, strawberries, roses, pink hydrangeas.
• Sulfur: potatoes 2.1 lb/100 sq ft over 2 applications; blueberries 3.2 lb/100 sq ft over 2 applications; azaleas and rhododendrons 2.8 lb/100 sq ft over 2 applications; blue hydrangeas 2.8 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.42, 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 897,214 surveyed acres in Fremont, ID, 43% are moderately acidic (5.5-6.5), 40% are near neutral (6.5-7.3), 11% are alkaline (above 7.3), 6% are strongly acidic (below 5.5). Mapped soils run from pH 5 to 8.2, a spread of 3.2 units across 514 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 12.2% clay and 3.28% 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).

Fremont against the rest of Idaho

pH 6.42 is 0.59 below the Idaho median of 7.01. 7 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: Boundary (6.29), Clearwater (6.32), Shoshone (6.32), Bonner (6.38), Kootenai (6.44), Idaho (6.46), Lewis (6.46), Benewah (6.49).

The range in Idaho runs from Valley at 6.04 to Jefferson at 8.06; Fremont sits 19% of the way up.