Soil pH in Monroe, AR: Lime or Sulfur?

Typical topsoil pH in Monroe, AR

Typical topsoil in Monroe, AR is pH 6.05, already right for vegetable garden (6-7). Test before adding anything.

What Monroe needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, strawberries, roses, pink hydrangeas.
• Just outside, test first: tomatoes (off by 0.2), potatoes (off by 0), azaleas and rhododendrons (off by 0).
• Sulfur: blueberries 2.3 lb/100 sq ft over 2 applications; blue hydrangeas 1.8 lb/100 sq ft.

What to do next

If your test lands near 6.05, 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 361,989 surveyed acres in Monroe, AR, 51% are moderately acidic (5.5-6.5), 33% are near neutral (6.5-7.3), 16% are strongly acidic (below 5.5). Mapped soils run from pH 4.8 to 7.3, a spread of 2.5 units across 52 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 24.8% clay and 1.91% 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. 7% of mapped components carry free carbonate (lime already in the ground).

Monroe against the rest of Arkansas

pH 6.05 is 0.61 above the Arkansas median of 5.44. 70 of 75 Arkansas counties have more acidic topsoil. Nationally it is level with than the US county median of 6.05.

Closest in pH within the state: Miller (5.94), Little River (5.95), Poinsett (5.97), Chicot (6.05), Phillips (6.12), Mississippi (6.32), Desha (6.33).

The range in Arkansas runs from Madison at 5.02 to Desha at 6.33; Monroe sits 79% of the way up.