Soil pH in Plumas, CA: Lime or Sulfur?

Typical topsoil pH in Plumas, CA

Typical topsoil in Plumas, CA is pH 6.4, already right for vegetable garden (6-7). Test before adding anything.

What Plumas needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, strawberries, roses, pink hydrangeas.
• Sulfur: potatoes 2.1 lb/100 sq ft over 2 applications; blueberries 3.2 lb/100 sq ft over 2 applications; azaleas and rhododendrons 2.8 lb/100 sq ft over 2 applications; blue hydrangeas 2.8 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.4, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, tomatoes, strawberries, roses, pink hydrangeas.

How mixed the soil is

Of the 1,486,903 surveyed acres in Plumas, CA, 50% are moderately acidic (5.5-6.5), 48% are near neutral (6.5-7.3), 2% are strongly acidic (below 5.5). Mapped soils run from pH 4 to 8, a spread of 4 units across 899 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 14.3% clay and 3.1% 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. None of the mapped components carry free carbonate.

Plumas against the rest of California

pH 6.4 is 0.14 below the California median of 6.54. 24 of 58 California counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Sacramento (6.29), Trinity (6.29), Glenn (6.34), Napa (6.37), Santa Cruz (6.42), Santa Clara (6.44), San Diego (6.46), San Francisco (6.5).

The range in California runs from Del Norte at 5.43 to Imperial at 8.16; Plumas sits 36% of the way up.