Soil pH in Putnam, TN: Lime or Sulfur?

Typical topsoil pH in Putnam, TN

Typical topsoil in Putnam, 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 Putnam 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 238,088 surveyed acres in Putnam, TN, 59% are strongly acidic (below 5.5), 31% are moderately acidic (5.5-6.5), 10% are near neutral (6.5-7.3). Mapped soils run from pH 4.3 to 7, a spread of 2.7 units across 237 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 19.5% clay and 2% 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.

Putnam 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: White (5.26), DeKalb (5.27), Loudon (5.27), Gibson (5.29), Bradley (5.3), Franklin (5.31), Rhea (5.31), Carroll (5.35).

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