Soil pH in Clay, TX: Lime or Sulfur?

Typical topsoil pH in Clay, TX

Typical topsoil in Clay, TX is pH 6.76, already right for vegetable garden (6-7). Test before adding anything.

What Clay needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, roses.
• Sulfur: potatoes 3 lb/100 sq ft over 2 applications; strawberries 1.8 lb/100 sq ft; blueberries 4.1 lb/100 sq ft over 3 applications; azaleas and rhododendrons 3.5 lb/100 sq ft over 2 applications; blue hydrangeas 3.5 lb/100 sq ft over 2 applications; pink hydrangeas 1.2 lb/100 sq ft.

What to do next

If your test lands near 6.76, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, tomatoes, roses.

How mixed the soil is

Of the 622,360 surveyed acres in Clay, TX, 60% are near neutral (6.5-7.3), 26% are moderately acidic (5.5-6.5), 14% are alkaline (above 7.3). Mapped soils run from pH 5.8 to 8.2, a spread of 2.4 units across 71 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 20.5% clay and 1.81% 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. 17% of mapped components carry free carbonate (lime already in the ground).

Clay against the rest of Texas

pH 6.76 is 0.67 below the Texas median of 7.43. 65 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: Fort Bend (6.71), Lavaca (6.71), Limestone (6.73), Wheeler (6.75), Kaufman (6.76), Fayette (6.77), Eastland (6.81), Montague (6.82).

The range in Texas runs from Hardin at 4.64 to Upton at 8.19; Clay sits 60% of the way up.