Soil pH in Josephine, OR: Lime or Sulfur?

Typical topsoil pH in Josephine, OR

Typical topsoil in Josephine, OR is pH 6.18, already right for vegetable garden (6-7). Test before adding anything.

What Josephine needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, strawberries, roses, pink hydrangeas.
• Just outside, test first: tomatoes (off by 0), potatoes (off by 0.2), azaleas and rhododendrons (off by 0.2).
• Sulfur: blueberries 2.8 lb/100 sq ft over 2 applications; blue hydrangeas 2.1 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.18, 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 959,411 surveyed acres in Josephine, OR, 75% are moderately acidic (5.5-6.5), 25% are near neutral (6.5-7.3). Mapped soils run from pH 4.8 to 7, a spread of 2.2 units across 574 soil components. 75% 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 21.3% clay and 3.82% 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.

Josephine against the rest of Oregon

pH 6.18 is 0.12 below the Oregon median of 6.3. 16 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: Linn (5.7), Multnomah (5.72), Douglas (5.73), Marion (5.75), Jackson (6.29), Hood River (6.31), Grant (6.43), Wheeler (6.58).

The range in Oregon runs from Clatsop at 4.89 to Malheur at 7.9; Josephine sits 43% of the way up.