Soil pH in Mason, WA: Lime or Sulfur?

Typical topsoil pH in Mason, WA

Typical topsoil in Mason, WA is pH 5.4, too acidic for vegetable garden. Expect roughly 7.7 lb of lime per 100 sq ft, but only after a soil test confirms it.

What Mason needs, by plant

• Already in range: potatoes, blueberries, azaleas and rhododendrons, blue hydrangeas.
• Just outside, test first: strawberries (off by 0.1).
• Lime: lawn (cool-season grass) 7.7 lb/100 sq ft over 2 applications; vegetable garden 7.7 lb/100 sq ft over 2 applications; tomatoes 7.7 lb/100 sq ft over 2 applications; roses 7.7 lb/100 sq ft over 2 applications; pink hydrangeas 5.6 lb/100 sq ft over 2 applications.

What to do next

If your test confirms pH near 5.4, spread about 77 lb of ground limestone per 1,000 sq ft of vegetable bed in 2 doses, ideally in fall.

How mixed the soil is

Of the 512,703 surveyed acres in Mason, WA, 54% are strongly acidic (below 5.5), 46% are moderately acidic (5.5-6.5). Mapped soils run from pH 4 to 6.5, a spread of 2.5 units across 282 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 9.1% clay and 8.19% organic matter, which this site treats as loam. At 8.19% organic matter the soil buffers like a heavier one, which pushes it into the loam bracket. 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.

Mason against the rest of Washington

pH 5.4 is 1.01 below the Washington median of 6.41. 6 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: Wahkiakum (5.05), Lewis (5.08), Clallam (5.23), Jefferson (5.24), Whatcom (5.41), King (5.45), Pierce (5.48), Kitsap (5.49).

The range in Washington runs from Grays Harbor at 4.93 to Adams at 7.45; Mason sits 19% of the way up.