Soil pH in Frio, TX: Lime or Sulfur?

Typical topsoil pH in Frio, TX

Typical topsoil in Frio, TX is pH 7.02, just outside the 6-7 range for vegetable garden. Test first; it may need nothing.

What Frio needs, by plant

• Just outside, test first: lawn (cool-season grass) (off by 0), vegetable garden (off by 0), tomatoes (off by 0.2), roses (off by 0).
• Sulfur: potatoes 3.5 lb/100 sq ft over 2 applications; strawberries 2.3 lb/100 sq ft over 2 applications; blueberries 4.6 lb/100 sq ft over 3 applications; azaleas and rhododendrons 4.1 lb/100 sq ft over 3 applications; blue hydrangeas 4.1 lb/100 sq ft over 3 applications; pink hydrangeas 1.8 lb/100 sq ft.

What to do next

If your test lands near 7.02, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, tomatoes, roses.

How mixed the soil is

Of the 619,475 surveyed acres in Frio, TX, 75% are near neutral (6.5-7.3), 26% are alkaline (above 7.3). Mapped soils run from pH 6.5 to 8.2, a spread of 1.7 units across 63 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 20.2% clay and 1.46% 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. 27% of mapped components carry free carbonate (lime already in the ground).

Frio against the rest of Texas

pH 7.02 is 0.41 below the Texas median of 7.43. 80 of 254 Texas counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Milam (6.94), Brazoria (6.98), Kenedy (6.98), Mason (6.99), Galveston (7.03), Navarro (7.03), Young (7.03), Calhoun (7.04).

The range in Texas runs from Hardin at 4.64 to Upton at 8.19; Frio sits 67% of the way up.