Soil pH in Jackson, OR: Lime or Sulfur?

Typical topsoil pH in Jackson, OR

Typical topsoil in Jackson, OR is pH 6.29, already right for vegetable garden (6-7). Test before adding anything.

What Jackson 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 2.3 lb/100 sq ft over 2 applications; blue hydrangeas 2.3 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.29, 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 1,283,149 surveyed acres in Jackson, OR, 68% are moderately acidic (5.5-6.5), 31% are near neutral (6.5-7.3). Mapped soils run from pH 5 to 7.6, a spread of 2.6 units across 2,217 soil components. 68% 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 23.9% clay and 3.36% 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.

Jackson against the rest of Oregon

pH 6.29 is right at the Oregon median of 6.3. 17 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: Multnomah (5.72), Douglas (5.73), Marion (5.75), Josephine (6.18), Hood River (6.31), Grant (6.43), Wheeler (6.58), Klamath (6.7).

The range in Oregon runs from Clatsop at 4.89 to Malheur at 7.9; Jackson sits 47% of the way up.