Growing conditions in the Columbia Basin

The Columbia Basin of Washington State is a place of lush gardens, native and drought-tolerant vegetation and a variety of crops grown to feed our country and sent to other countries as well.

The climate in this area is generally considered high desert, but the ground is fertile. With the help of the Columbia Basin Irrigation Project, miles and miles of desert plains have been converted to irrigated cropland, parks and home gardens.

· Climate: The climate in this area has four seasons: winter, spring, summer, and fall. Temperatures can range from the occasional -20°F in the winter, to temperatures upwards of 100°F in the summer. In addition, wind speed plays a factor in gardening. While the wind is fairly mild during the summer months, high winds in late spring and fall can pose complications for successful growth of garden and landscape plants.

· Soil: Typically, the soil is quite fertile with adequate nutrient management. However, depending on where you live in Grant or Adams Counties, the soil could be silty, sandy, rocky, shallow or deep.

· Growing Season: The growing season is long, but winter conditions are not conducive to gardening. Generally speaking, the growing season begins in late February for plants like lettuce, onions, garlic and other cold-loving plants. At times, there may still be snow on the ground as late as early March. The growing season typically ends with the first heavy frost, which can come in mid to late October to mid to late November, depending on weather conditions.

· Humidity: The limiting factor most often for growing beautiful plants, trees, and shrubs in our area is not cold, but humidity and lack of water. The porous soil and dry air make life hard for certain species of shrub and trees. As gardeners we learn to protect plants from the heat and dry winds, add the missing organic materials to our soil, and mulch to retain water.

· Hardiness Zones: These are general guidelines of the temperatures a plant can survive. Zone 5 plants can survive winter temperatures no lower than -20°F (-28° C.). If a plant is hardy in zones 5-8, it can be grown in zones 5, 6, 7 and 8. It would probably not survive the cold winter temperatures in zone 4 or lower. It also could probably not survive the hot, dry summers and inadequate time for dormancy in zone 9 or higher.

For answers to gardening questions, contact the Master Gardeners at the WSU Grant-Adams Extension office at 754-2011, ext. 4313 or email your gardening questions to ga.mgvolunteers@wsu.edu. Visit our web page at grant-adams.wsu.edu.