Soil pH in Plaquemines, LA: Lime or Sulfur?

Typical topsoil pH in Plaquemines, LA

Typical topsoil in Plaquemines, LA is pH 6.71, already right for vegetable garden (6-7). Test before adding anything.

What Plaquemines needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, roses.
• Just outside, test first: strawberries (off by 0.2), pink hydrangeas (off by 0.2).
• Sulfur: potatoes 4.1 lb/100 sq ft over 3 applications; blueberries 5.8 lb/100 sq ft over 3 applications; azaleas and rhododendrons 5.1 lb/100 sq ft over 3 applications; blue hydrangeas 5.1 lb/100 sq ft over 3 applications.

What to do next

If your test lands near 6.71, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, tomatoes, strawberries, roses, pink hydrangeas.

How mixed the soil is

Of the 331,753 surveyed acres in Plaquemines, LA, 71% are near neutral (6.5-7.3), 16% are moderately acidic (5.5-6.5), 10% are alkaline (above 7.3), 3% are strongly acidic (below 5.5). Mapped soils run from pH 5.1 to 8, a spread of 2.9 units across 64 soil components. 71% 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 58.9% clay and 6.53% organic matter, which this site treats as clay. At 6.53% organic matter the soil buffers like a heavier one, which pushes it into the clay bracket. Moving it one pH unit takes about 11.5 lb of lime or 3.4 lb of sulfur per 100 sq ft. 3% of mapped components carry free carbonate (lime already in the ground).

Plaquemines against the rest of Louisiana

pH 6.71 is 1.17 above the Louisiana median of 5.54. 58 of 64 Louisiana counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Iberia (6.49), St. Mary (6.52), St. Charles (6.53), Orleans (6.61), St. James (6.76), St. John the Baptist (6.78), Pointe Coupee (6.84), West Baton Rouge (6.9).

The range in Louisiana runs from Allen at 4.88 to St. Bernard at 7; Plaquemines sits 86% of the way up.