Soil pH in Gibson, TN: Lime or Sulfur?

Typical topsoil pH in Gibson, TN

Typical topsoil in Gibson, TN is pH 5.29, too acidic for vegetable garden. Expect roughly 8.4 lb of lime per 100 sq ft, but only after a soil test confirms it.

What Gibson needs, by plant

• Already in range: potatoes, blueberries, azaleas and rhododendrons, blue hydrangeas.
• Just outside, test first: strawberries (off by 0.2).
• Lime: lawn (cool-season grass) 8.4 lb/100 sq ft over 2 applications; vegetable garden 8.4 lb/100 sq ft over 2 applications; tomatoes 8.4 lb/100 sq ft over 2 applications; roses 8.4 lb/100 sq ft over 2 applications; pink hydrangeas 7 lb/100 sq ft over 2 applications.

What to do next

If your test confirms pH near 5.29, spread about 84 lb of ground limestone per 1,000 sq ft of vegetable bed in 2 doses, ideally in fall.

How mixed the soil is

Of the 365,313 surveyed acres in Gibson, TN, 88% are strongly acidic (below 5.5), 12% are moderately acidic (5.5-6.5). Mapped soils run from pH 5 to 6.5, a spread of 1.5 units across 42 soil components. 88% 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 14.8% clay and 1.49% 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.

Gibson against the rest of Tennessee

pH 5.29 is 0.06 below the Tennessee median of 5.35. 42 of 95 Tennessee counties have more acidic topsoil. Nationally it is more acidic than the US county median of 6.05.

Closest in pH within the state: Fayette (5.25), White (5.26), DeKalb (5.27), Loudon (5.27), Putnam (5.29), Bradley (5.3), Franklin (5.31), Rhea (5.31).

The range in Tennessee runs from Bledsoe at 4.78 to Lake at 6.59; Gibson sits 28% of the way up.