Soil pH in Lake, OR: Lime or Sulfur?

Typical topsoil pH in Lake, OR

Typical topsoil in Lake, OR is pH 7.46, too alkaline for vegetable garden. Expect roughly 2.3 lb of sulfur per 100 sq ft, but only after a soil test confirms it.

What Lake needs, by plant

• Sulfur: lawn (cool-season grass) 2.3 lb/100 sq ft over 2 applications; vegetable garden 2.3 lb/100 sq ft over 2 applications; tomatoes 2.3 lb/100 sq ft over 2 applications; potatoes 4.6 lb/100 sq ft over 3 applications; strawberries 3.5 lb/100 sq ft over 2 applications; roses 2.3 lb/100 sq ft over 2 applications; blueberries 5.8 lb/100 sq ft over 3 applications; azaleas and rhododendrons 5.1 lb/100 sq ft over 3 applications; blue hydrangeas 5.1 lb/100 sq ft over 3 applications; pink hydrangeas 2.8 lb/100 sq ft over 2 applications.

What to do next

If your test confirms pH near 7.46, work in about 23 lb of elemental sulfur per 1,000 sq ft of vegetable bed in 2 doses.

How mixed the soil is

Of the 3,958,148 surveyed acres in Lake, OR, 56% are alkaline (above 7.3), 38% are near neutral (6.5-7.3), 6% are moderately acidic (5.5-6.5). Mapped soils run from pH 5 to 10.1, a spread of 5.1 units across 2,410 soil components. No single class covers 60% of the county, so two gardens a few miles apart here can need opposite treatments. Test your own bed.

Clay, organic matter and rates

Topsoil here averages 16.1% clay and 1.68% 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. 8% of mapped components carry free carbonate (lime already in the ground).

Lake against the rest of Oregon

pH 7.46 is 1.16 above the Oregon median of 6.3. 33 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: Umatilla (6.96), Gilliam (6.99), Morrow (7.04), Baker (7.1), Harney (7.47), Malheur (7.9).

The range in Oregon runs from Clatsop at 4.89 to Malheur at 7.9; Lake sits 85% of the way up.