Soil pH in Wallowa, OR: Lime or Sulfur?

Typical topsoil pH in Wallowa, OR

Typical topsoil in Wallowa, OR is pH 6.72, already right for vegetable garden (6-7). Test before adding anything.

What Wallowa 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 3.5 lb/100 sq ft over 2 applications; blue hydrangeas 3.5 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.72, 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 774,122 surveyed acres in Wallowa, OR, 87% are near neutral (6.5-7.3), 11% are moderately acidic (5.5-6.5), 2% are alkaline (above 7.3). Mapped soils run from pH 5.4 to 8.2, a spread of 2.8 units across 677 soil components. 87% 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 18.8% clay and 3.41% 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. 1% of mapped components carry free carbonate (lime already in the ground).

Wallowa against the rest of Oregon

pH 6.72 is 0.42 above the Oregon median of 6.3. 22 of 36 Oregon counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Hood River (6.31), Grant (6.43), Wheeler (6.58), Klamath (6.7), Deschutes (6.75), Wasco (6.78), Crook (6.86), Jefferson (6.87).

The range in Oregon runs from Clatsop at 4.89 to Malheur at 7.9; Wallowa sits 61% of the way up.