Soil pH in Pinal, AZ: Lime or Sulfur?

Typical topsoil pH in Pinal, AZ

Typical topsoil in Pinal, AZ is pH 7.74 and calcareous, so sulfur won't lower it for long. For vegetable garden, choose alkaline-tolerant varieties and add compost rather than fighting the soil.

What Pinal needs, by plant

• Beds or pots instead: lawn (cool-season grass), vegetable garden, tomatoes, potatoes, strawberries, roses, blueberries, azaleas and rhododendrons, blue hydrangeas, pink hydrangeas.

What to do next

If your test confirms pH near 7.74, consider raised beds for anything acid-loving; with 71% of soils here carrying free lime, sulfur will not hold.

How mixed the soil is

Of the 2,579,738 surveyed acres in Pinal, AZ, 75% are alkaline (above 7.3), 24% are near neutral (6.5-7.3), 2% are moderately acidic (5.5-6.5). Mapped soils run from pH 6 to 8.8, a spread of 2.8 units across 485 soil components. 75% 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 16.2% clay and 0.77% 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. 71% of mapped components carry free carbonate (lime already in the ground), enough that sulfur gets neutralised before it does much.

Pinal against the rest of Arizona

pH 7.74 is right at the Arizona median of 7.77. 6 of 14 Arizona counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Yavapai (7.42), Greenlee (7.44), Cochise (7.46), Pima (7.56), Apache (7.79), Coconino (7.81), Mohave (7.83), Navajo (7.84).

The range in Arizona runs from Gila at 7.17 to Maricopa at 8.12; Pinal sits 60% of the way up.