Soil pH in Denali Borough, AK: Lime or Sulfur?

Typical topsoil pH in Denali Borough, AK

Typical topsoil in Denali Borough, AK is pH 5.94, just outside the 6-7 range for vegetable garden. Test first; it may need nothing.

What Denali Borough needs, by plant

• Already in range: potatoes, strawberries, azaleas and rhododendrons.
• Just outside, test first: lawn (cool-season grass) (off by 0.1), vegetable garden (off by 0.1), roses (off by 0.1), pink hydrangeas (off by 0.1).
• Lime: tomatoes 1.8 lb/100 sq ft.
• Sulfur: blueberries 1.1 lb/100 sq ft; blue hydrangeas 0.8 lb/100 sq ft.

What to do next

If your test lands near 5.94, 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 75,727 surveyed acres in Denali Borough, AK, 74% are moderately acidic (5.5-6.5), 13% are strongly acidic (below 5.5), 13% are near neutral (6.5-7.3). Mapped soils run from pH 4.8 to 6.8, a spread of 2 units across 107 soil components. 74% 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 6.9% clay and 4.62% organic matter, which this site treats as sandy. Moving it one pH unit takes about 3 lb of lime or 1.2 lb of sulfur per 100 sq ft. None of the mapped components carry free carbonate.

Denali Borough against the rest of Alaska

pH 5.94 is 0.68 above the Alaska median of 5.26. 24 of 27 Alaska counties have more acidic topsoil. Nationally it is more acidic than the US county median of 6.05.

Closest in pH within the state: Bethel Census Area (5.57), North Slope Borough (5.62), Southeast Fairbanks Census Area (5.66), Yukon-Koyukuk Census Area (5.9), Hoonah-Angoon Census Area (6.06), Yakutat City and Borough (6.08).

The range in Alaska runs from Ketchikan Gateway Borough at 4.52 to Yakutat City and Borough at 6.08; Denali Borough sits 91% of the way up.