Soil pH in Valley, ID: Lime or Sulfur?

Typical topsoil pH in Valley, ID

Typical topsoil in Valley, ID is pH 6.04, already right for vegetable garden (6-7). Test before adding anything.

What Valley needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, strawberries, roses, pink hydrangeas.
• Just outside, test first: tomatoes (off by 0.2), potatoes (off by 0), azaleas and rhododendrons (off by 0).
• Sulfur: blueberries 1.2 lb/100 sq ft; blue hydrangeas 1 lb/100 sq ft.

What to do next

If your test lands near 6.04, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, tomatoes, potatoes, strawberries, roses, azaleas and rhododendrons, pink hydrangeas.

How mixed the soil is

Of the 350,336 surveyed acres in Valley, ID, 61% are moderately acidic (5.5-6.5), 23% are near neutral (6.5-7.3), 16% are strongly acidic (below 5.5). Mapped soils run from pH 5 to 6.7, a spread of 1.7 units across 148 soil components. 61% 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 9.6% clay and 2.59% 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.

Valley against the rest of Idaho

pH 6.04 is 0.97 below the Idaho median of 7.01. 0 of 44 Idaho counties have more acidic topsoil. Nationally it is more acidic than the US county median of 6.05.

Closest in pH within the state: Latah (6.18), Boise (6.25), Boundary (6.29), Clearwater (6.32).