Soil pH in Placer, CA: Lime or Sulfur?

Typical topsoil pH in Placer, CA

Typical topsoil in Placer, CA is pH 6.13, already right for vegetable garden (6-7). Test before adding anything.

What Placer needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, strawberries, roses, pink hydrangeas.
• Just outside, test first: tomatoes (off by 0.1), potatoes (off by 0.1), azaleas and rhododendrons (off by 0.1).
• Sulfur: blueberries 2.5 lb/100 sq ft over 2 applications; blue hydrangeas 2.1 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.13, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, tomatoes, potatoes, strawberries, roses, azaleas and rhododendrons, pink hydrangeas.

How mixed the soil is

Of the 401,976 surveyed acres in Placer, CA, 82% are moderately acidic (5.5-6.5), 14% are near neutral (6.5-7.3), 3% are alkaline (above 7.3), 2% are strongly acidic (below 5.5). Mapped soils run from pH 5 to 8.2, a spread of 3.2 units across 639 soil components. 82% 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 15% clay and 3.55% 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.

Placer against the rest of California

pH 6.13 is 0.41 below the California median of 6.54. 11 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: Mendocino (6.05), Sonoma (6.08), San Benito (6.09), Marin (6.11), Alpine (6.14), Calaveras (6.17), Shasta (6.17), Tehama (6.2).

The range in California runs from Del Norte at 5.43 to Imperial at 8.16; Placer sits 26% of the way up.