Soil pH in Ketchikan Gateway Borough, AK: Lime or Sulfur?

Typical topsoil pH in Ketchikan Gateway Borough, AK

Typical topsoil in Ketchikan Gateway Borough, AK is pH 4.52, too acidic for vegetable garden. Expect roughly 6 lb of lime per 100 sq ft, but only after a soil test confirms it.

What Ketchikan Gateway Borough needs, by plant

• Already in range: blueberries, azaleas and rhododendrons.
• Lime: lawn (cool-season grass) 6 lb/100 sq ft over 2 applications; vegetable garden 6 lb/100 sq ft over 2 applications; tomatoes 6 lb/100 sq ft over 2 applications; potatoes 3 lb/100 sq ft; strawberries 4.5 lb/100 sq ft; roses 6 lb/100 sq ft over 2 applications; blue hydrangeas 2.1 lb/100 sq ft; pink hydrangeas 5.1 lb/100 sq ft over 2 applications.

What to do next

If your test confirms pH near 4.52, spread about 60 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 0 surveyed acres in Ketchikan Gateway Borough, AK, 92% are strongly acidic (below 5.5), 8% are moderately acidic (5.5-6.5). Mapped soils run from pH 3.8 to 6.8, a spread of 3 units across 817 soil components. 92% 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 4.6% clay and 4.66% 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.

Ketchikan Gateway Borough against the rest of Alaska

pH 4.52 is 0.74 below the Alaska median of 5.26. 0 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).