Soil pH in Kalawao, HI: Lime or Sulfur?

Typical topsoil pH in Kalawao, HI

Typical topsoil in Kalawao, HI is pH 6.6, already right for vegetable garden (6-7). Test before adding anything.

What Kalawao needs, by plant

• Already in range: lawn (cool-season grass), vegetable garden, tomatoes, roses.
• Just outside, test first: strawberries (off by 0.1), pink hydrangeas (off by 0.1).
• Sulfur: potatoes 3.7 lb/100 sq ft over 2 applications; blueberries 5.4 lb/100 sq ft over 3 applications; azaleas and rhododendrons 4.4 lb/100 sq ft over 3 applications; blue hydrangeas 4.4 lb/100 sq ft over 3 applications.

What to do next

If your test lands near 6.6, 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 1,156 surveyed acres in Kalawao, HI, 100% are near neutral (6.5-7.3). Mapped soils run from pH 6.6 to 6.6, a spread of 0 units across 1 soil components. 100% 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 35% clay and 5% organic matter, which this site treats as clay. Moving it one pH unit takes about 11.5 lb of lime or 3.4 lb of sulfur per 100 sq ft. None of the mapped components carry free carbonate.

Kalawao against the rest of Hawaii

pH 6.6 is 0.77 above the Hawaii median of 5.83. 4 of 5 Hawaii counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Kauai (5.26), Honolulu (5.81), Maui (5.83), Hawaii (6.01).