Soil pH in Madison, KY: Lime or Sulfur?

Typical topsoil pH in Madison, KY

Typical topsoil in Madison, KY is pH 6.14, already right for vegetable garden (6-7). Test before adding anything.

What Madison needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, strawberries, roses, pink hydrangeas.
• Just outside, test first: tomatoes (off by 0.1), potatoes (off by 0.1), azaleas and rhododendrons (off by 0.1).
• Sulfur: blueberries 2.5 lb/100 sq ft over 2 applications; blue hydrangeas 2.1 lb/100 sq ft over 2 applications.

What to do next

If your test lands near 6.14, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, tomatoes, potatoes, strawberries, roses, azaleas and rhododendrons, pink hydrangeas.

How mixed the soil is

Of the 238,687 surveyed acres in Madison, KY, 38% are moderately acidic (5.5-6.5), 35% are near neutral (6.5-7.3), 19% are strongly acidic (below 5.5), 8% are alkaline (above 7.3). Mapped soils run from pH 4.5 to 7.9, a spread of 3.4 units across 211 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 23.5% clay and 2.44% 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. 19% of mapped components carry free carbonate (lime already in the ground).

Madison against the rest of Kentucky

pH 6.14 is 0.35 above the Kentucky median of 5.79. 95 of 120 Kentucky counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Owen (6.12), Bracken (6.13), Henderson (6.13), Shelby (6.13), Pendleton (6.14), Robertson (6.18), Union (6.19), Boyle (6.21).

The range in Kentucky runs from Greenup at 5.09 to Carroll at 6.63; Madison sits 68% of the way up.