Soil pH in Dillingham Census Area, AK: Lime or Sulfur?
Typical topsoil pH in Dillingham Census Area, AK
Typical topsoil in Dillingham Census Area, AK is pH 4.94, too acidic for vegetable garden. Expect roughly 11.2 lb of lime per 100 sq ft, but only after a soil test confirms it.
What Dillingham Census Area needs, by plant
- Already in range: blueberries, azaleas and rhododendrons.
- Just outside, test first: potatoes (off by 0.1), blue hydrangeas (off by 0.1).
- Lime: lawn (cool-season grass) 11.2 lb/100 sq ft over 3 applications; vegetable garden 11.2 lb/100 sq ft over 3 applications; tomatoes 11.2 lb/100 sq ft over 3 applications; strawberries 7.7 lb/100 sq ft over 2 applications; roses 11.2 lb/100 sq ft over 3 applications; pink hydrangeas 9.1 lb/100 sq ft over 2 applications.
What to do next
If your test confirms pH near 4.94, spread about 112 lb of ground limestone per 1,000 sq ft of vegetable bed in 3 doses, ideally in fall.
How mixed the soil is
Of the 8,673,194 surveyed acres in Dillingham Census Area, AK, 69% are strongly acidic (below 5.5), 30% are moderately acidic (5.5-6.5), 1% are near neutral (6.5-7.3). Mapped soils run from pH 3.5 to 7.3, a spread of 3.8 units across 760 soil components. 69% 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 6.5% clay and 12.46% organic matter, which this site treats as loam. At 12.46% 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. None of the mapped components carry free carbonate.
Dillingham Census Area against the rest of Alaska
pH 4.94 is 0.32 below the Alaska median of 5.26. 5 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: Lake and Peninsula Borough (4.83), Skagway Borough (4.84), Kenai Peninsula Borough (4.85), Anchorage Borough (4.89), Wrangell-Petersburg Census Area (4.94), Kodiak Island Borough (4.96), Kusilvak Census Area (old Wade Hampton) (5.04), Haines Borough (5.1).
The range in Alaska runs from Ketchikan Gateway Borough at 4.52 to Yakutat City and Borough at 6.08; Dillingham Census Area sits 27% of the way up.