Soil pH in Bonneville, ID: Lime or Sulfur?

Typical topsoil pH in Bonneville, ID

Typical topsoil in Bonneville, ID is pH 7.1, just outside the 6-7 range for vegetable garden. Test first; it may need nothing.

What Bonneville needs, by plant

• Just outside, test first: lawn (cool-season grass) (off by 0.1), vegetable garden (off by 0.1), roses (off by 0.1).
• Beds or pots instead: tomatoes, potatoes, strawberries, blueberries, azaleas and rhododendrons, blue hydrangeas, pink hydrangeas.

What to do next

If your test lands near 7.1, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, roses.

How mixed the soil is

Of the 889,201 surveyed acres in Bonneville, ID, 48% are near neutral (6.5-7.3), 38% are alkaline (above 7.3), 14% are moderately acidic (5.5-6.5). Mapped soils run from pH 5.6 to 8.2, a spread of 2.6 units across 350 soil components. No single class covers 60% of the county, so two gardens a few miles apart here can need opposite treatments. Test your own bed.

Clay, organic matter and rates

Topsoil here averages 17.5% clay and 3.25% organic matter, which this site treats as loam. Moving it one pH unit takes about 7 lb of lime or 2.3 lb of sulfur per 100 sq ft. 31% of mapped components carry free carbonate (lime already in the ground), enough that sulfur gets neutralised before it does much.

Bonneville against the rest of Idaho

pH 7.1 is 0.09 above the Idaho median of 7.01. 24 of 44 Idaho counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Gem (6.99), Lincoln (7.01), Owyhee (7.02), Gooding (7.04), Ada (7.18), Bear Lake (7.18), Clark (7.19), Elmore (7.26).

The range in Idaho runs from Valley at 6.04 to Jefferson at 8.06; Bonneville sits 52% of the way up.