Soil Types in Wyoming

Wyoming has 139 zip codes in our database. The most common soil type is Loam, found in 0% of the state. Understanding your local soil type helps you choose the right plants and amendments for your garden.

Wyoming spans USDA hardiness zones 4a through 5b. Your hardiness zone determines which perennial plants will survive winter in your area. Enter your zip code above to find your exact zone and get personalized planting recommendations.

Wyoming is the least populated state, and its soils reflect a landscape dominated by grassland, mountain, and high desert. The eastern plains have mixed-grass prairie soils — alkaline, relatively thin, and adapted to low rainfall. The Bighorn Basin in north-central Wyoming has arid desert soils similar to Nevada, with alkaline conditions and salt accumulations. The mountains — the Wind River, Bighorn, Teton, and Absaroka Ranges — have thin, rocky, acidic soils at high elevation transitioning to deeper forest soils in the valleys. The Powder River Basin has soils influenced by coal-bearing strata. Forkwood loam, the state soil, is a well-drained plains soil representative of Wyoming's rangeland. Yellowstone National Park's soils include unique thermal features where geothermal activity creates unusual mineral conditions.

Wyoming has one of the most challenging growing environments in the lower 48 states. Cheyenne at 6,000 feet averages about 130 frost-free days, with the last frost near May 15 and first frost around September 25. Casper has 120 days. Sheridan has 115-120 days. Mountain communities and high valleys may have fewer than 60 frost-free days. Wyoming is also the windiest state, which increases evapotranspiration and can physically damage plants. The combination of short season, high altitude UV radiation, wind, low humidity, and temperature swings makes gardening genuinely difficult. Yet dedicated Wyoming gardeners produce impressive harvests by embracing season extension and wind protection.

Wyoming gardening favors tough, fast-maturing crops. Potatoes are the safest vegetable bet, thriving in the cool climate and producing well in Wyoming's loamy soils. Peas, lettuce, radishes, kale, spinach, and carrots are reliable cool-season performers. Short-season beans produce in most areas. Root vegetables — particularly carrots, beets, and turnips — develop excellent flavor in the cool conditions and mineral-rich soils. Hardy herbs like chives, sage, and thyme survive Wyoming winters. In the warmer valleys (Thermopolis, Cody), short-season tomatoes can produce with wind protection and season extension. Wyoming's ranching heritage means excellent composted manure is widely available for soil building.

The University of Wyoming Extension provides soil testing through the UW Analytical Laboratory. Most Wyoming soils are alkaline (pH 7.0-8.5) with low organic matter and nitrogen. Adding compost is the single most impactful improvement. Wind protection is as important as soil quality for Wyoming gardens — install windbreaks, use cold frames, or grow in the shelter of buildings. Hoop houses and high tunnels have transformed Wyoming gardening, allowing many growers to extend the season by 6-8 weeks in each direction. Drip irrigation is essential since rainfall is typically under 15 inches statewide. The intense UV at high altitude can actually stress plants — shade cloth during the hottest afternoon hours helps prevent sunscald on tender crops.