Soil pH in Los Angeles, CA: Lime or Sulfur?

Typical topsoil pH in Los Angeles, CA

Typical topsoil in Los Angeles, CA is pH 6.72, already right for vegetable garden (6-7). Test before adding anything.

What Los Angeles needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, roses.
• Just outside, test first: strawberries (off by 0.2), pink hydrangeas (off by 0.2).
• Sulfur: potatoes 2.8 lb/100 sq ft over 2 applications; blueberries 3.9 lb/100 sq ft over 2 applications; azaleas and rhododendrons 3.5 lb/100 sq ft over 2 applications; blue hydrangeas 3.5 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.72, 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 1,959,457 surveyed acres in Los Angeles, CA, 71% are near neutral (6.5-7.3), 16% are moderately acidic (5.5-6.5), 12% are alkaline (above 7.3), 1% are strongly acidic (below 5.5). Mapped soils run from pH 4.5 to 9.8, a spread of 5.3 units across 475 soil components. 71% 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 16.1% clay and 1.06% 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. 5% of mapped components carry free carbonate (lime already in the ground).

Los Angeles against the rest of California

pH 6.72 is 0.18 above the California median of 6.54. 34 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: Solano (6.63), Contra Costa (6.69), Santa Barbara (6.69), Sierra (6.71), Fresno (6.75), Siskiyou (6.75), Lassen (6.77), Mono (6.79).

The range in California runs from Del Norte at 5.43 to Imperial at 8.16; Los Angeles sits 47% of the way up.