Soil pH in Marion, KY: Lime or Sulfur?

Typical topsoil pH in Marion, KY

Typical topsoil in Marion, KY is pH 5.79, just outside the 6-7 range for vegetable garden. Test first; it may need nothing.

What Marion needs, by plant

• Already in range: potatoes, strawberries, azaleas and rhododendrons.
• Just outside, test first: lawn (cool-season grass) (off by 0.2), vegetable garden (off by 0.2), roses (off by 0.2), pink hydrangeas (off by 0.2).
• Lime: tomatoes 4.9 lb/100 sq ft.
• Sulfur: blueberries 1.8 lb/100 sq ft; blue hydrangeas 1.2 lb/100 sq ft.

What to do next

If your test lands near 5.79, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, potatoes, strawberries, roses, azaleas and rhododendrons, pink hydrangeas.

How mixed the soil is

Of the 190,707 surveyed acres in Marion, KY, 42% are moderately acidic (5.5-6.5), 30% are strongly acidic (below 5.5), 28% are near neutral (6.5-7.3). Mapped soils run from pH 4.6 to 7.9, a spread of 3.3 units across 141 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 23.7% clay and 2.11% 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. 2% of mapped components carry free carbonate (lime already in the ground).

Marion against the rest of Kentucky

pH 5.79 is right at the Kentucky median of 5.79. 60 of 120 Kentucky counties have more acidic topsoil. Nationally it is more acidic than the US county median of 6.05.

Closest in pH within the state: Caldwell (5.76), Logan (5.78), Meade (5.78), Crittenden (5.79), Metcalfe (5.8), Christian (5.81), Estill (5.84), Todd (5.84).

The range in Kentucky runs from Greenup at 5.09 to Carroll at 6.63; Marion sits 45% of the way up.