Soil pH in Grays Harbor, WA: Lime or Sulfur?

Typical topsoil pH in Grays Harbor, WA

Typical topsoil in Grays Harbor, WA is pH 4.93, too acidic for vegetable garden. Expect roughly 18.4 lb of lime per 100 sq ft, but only after a soil test confirms it.

What Grays Harbor needs, by plant

• Already in range: blueberries, azaleas and rhododendrons.
• Just outside, test first: potatoes (off by 0.1), blue hydrangeas (off by 0.1).
• Lime: lawn (cool-season grass) 18.4 lb/100 sq ft over 4 applications; vegetable garden 18.4 lb/100 sq ft over 4 applications; tomatoes 18.4 lb/100 sq ft over 4 applications; strawberries 12.7 lb/100 sq ft over 3 applications; roses 18.4 lb/100 sq ft over 4 applications; pink hydrangeas 15 lb/100 sq ft over 3 applications.

What to do next

If your test confirms pH near 4.93, spread about 184 lb of ground limestone per 1,000 sq ft of vegetable bed in 4 doses, ideally in fall.

How mixed the soil is

Of the 968,253 surveyed acres in Grays Harbor, WA, 86% are strongly acidic (below 5.5), 14% are moderately acidic (5.5-6.5). Mapped soils run from pH 3.8 to 7, a spread of 3.2 units across 405 soil components. 86% 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 16.4% clay and 11.21% organic matter, which this site treats as clay. At 11.21% 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.

Grays Harbor against the rest of Washington

pH 4.93 is 1.48 below the Washington median of 6.41. 0 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: Pacific (4.99), Wahkiakum (5.05), Lewis (5.08), Clallam (5.23).