Soil pH in Alamosa, CO: Lime or Sulfur?

Typical topsoil pH in Alamosa, CO

Typical topsoil in Alamosa, CO is pH 8.28 and calcareous, so sulfur won't lower it for long. For vegetable garden, choose alkaline-tolerant varieties and add compost rather than fighting the soil.

What Alamosa needs, by plant

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

What to do next

If your test confirms pH near 8.28, consider raised beds for anything acid-loving; with 64% of soils here carrying free lime, sulfur will not hold.

How mixed the soil is

Of the 412,768 surveyed acres in Alamosa, CO, 92% are alkaline (above 7.3), 6% are near neutral (6.5-7.3), 1% are moderately acidic (5.5-6.5). Mapped soils run from pH 4.6 to 9.6, a spread of 5 units across 144 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 12.7% clay and 1.11% 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. 64% of mapped components carry free carbonate (lime already in the ground), enough that sulfur gets neutralised before it does much.

Alamosa against the rest of Colorado

pH 8.28 is 1.11 above the Colorado median of 7.17. 62 of 63 Colorado counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Delta (7.8), Otero (7.82), Conejos (7.84), Rio Grande (7.92).