Soil pH in New Haven, CT: Lime or Sulfur?

Typical topsoil pH in New Haven, CT

Typical topsoil in New Haven, CT 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 New Haven 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 337,608 surveyed acres in New Haven, CT, 62% are strongly acidic (below 5.5), 35% are moderately acidic (5.5-6.5), 2% are near neutral (6.5-7.3). Mapped soils run from pH 3.8 to 7.8, a spread of 4 units across 1,135 soil components. 62% 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 8.3% clay and 5.6% organic matter, which this site treats as loam. At 5.6% organic matter the soil buffers like a heavier one, which pushes it into the loam bracket. Moving it one pH unit takes about 7 lb of lime or 2.3 lb of sulfur per 100 sq ft. 1% of mapped components carry free carbonate (lime already in the ground).

New Haven against the rest of Connecticut

pH 5.29 is 0.06 above the Connecticut median of 5.23. 6 of 8 Connecticut counties have more acidic topsoil. Nationally it is more acidic than the US county median of 6.05.

Closest in pH within the state: New London (5.14), Middlesex (5.21), Litchfield (5.25), Fairfield (5.26), Hartford (5.33).

The range in Connecticut runs from Tolland at 5.07 to Hartford at 5.33; New Haven sits 85% of the way up.