Soil pH in Deschutes, OR: Lime or Sulfur?

Typical topsoil pH in Deschutes, OR

Typical topsoil in Deschutes, OR is pH 6.75, already right for vegetable garden (6-7). Test before adding anything.

What Deschutes needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, roses.
• Sulfur: potatoes 1.6 lb/100 sq ft; strawberries 1 lb/100 sq ft; blueberries 2.2 lb/100 sq ft over 2 applications; azaleas and rhododendrons 1.8 lb/100 sq ft; blue hydrangeas 1.8 lb/100 sq ft; pink hydrangeas 0.6 lb/100 sq ft.

What to do next

If your test lands near 6.75, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, tomatoes, roses.

How mixed the soil is

Of the 1,737,123 surveyed acres in Deschutes, OR, 64% are near neutral (6.5-7.3), 28% are moderately acidic (5.5-6.5), 7% are alkaline (above 7.3), 1% are strongly acidic (below 5.5). Mapped soils run from pH 4.8 to 8.6, a spread of 3.8 units across 1,297 soil components. 64% 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 6.2% clay and 2.1% 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.

Deschutes against the rest of Oregon

pH 6.75 is 0.45 above the Oregon median of 6.3. 23 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: Grant (6.43), Wheeler (6.58), Klamath (6.7), Wallowa (6.72), Wasco (6.78), Crook (6.86), Jefferson (6.87), Union (6.89).

The range in Oregon runs from Clatsop at 4.89 to Malheur at 7.9; Deschutes sits 62% of the way up.