Soil pH in Clallam, WA: Lime or Sulfur?

Typical topsoil pH in Clallam, WA

Typical topsoil in Clallam, WA is pH 5.23, too acidic for vegetable garden. Expect roughly 15 lb of lime per 100 sq ft, but only after a soil test confirms it.

What Clallam needs, by plant

• Already in range: potatoes, blueberries, azaleas and rhododendrons, blue hydrangeas.
• Lime: lawn (cool-season grass) 15 lb/100 sq ft over 3 applications; vegetable garden 15 lb/100 sq ft over 3 applications; tomatoes 15 lb/100 sq ft over 3 applications; strawberries 9.2 lb/100 sq ft over 2 applications; roses 15 lb/100 sq ft over 3 applications; pink hydrangeas 11.5 lb/100 sq ft over 3 applications.

What to do next

If your test confirms pH near 5.23, spread about 150 lb of ground limestone per 1,000 sq ft of vegetable bed in 3 doses, ideally in fall.

How mixed the soil is

Of the 695,888 surveyed acres in Clallam, WA, 62% are strongly acidic (below 5.5), 34% are moderately acidic (5.5-6.5), 4% are near neutral (6.5-7.3). Mapped soils run from pH 4 to 7, a spread of 3 units across 371 soil components. 62% 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 13.2% clay and 9.81% organic matter, which this site treats as clay. At 9.81% organic matter the soil buffers like a heavier one, which pushes it into the clay bracket. Moving it one pH unit takes about 11.5 lb of lime or 3.4 lb of sulfur per 100 sq ft. None of the mapped components carry free carbonate.

Clallam against the rest of Washington

pH 5.23 is 1.18 below the Washington median of 6.41. 4 of 39 Washington counties have more acidic topsoil. Nationally it is more acidic than the US county median of 6.05.

Closest in pH within the state: Grays Harbor (4.93), Pacific (4.99), Wahkiakum (5.05), Lewis (5.08), Jefferson (5.24), Mason (5.4), Whatcom (5.41), King (5.45).

The range in Washington runs from Grays Harbor at 4.93 to Adams at 7.45; Clallam sits 12% of the way up.