Quick Reference to Columbia Basin Gardening

USDA Plant Hardiness Zone (click for map)

  • Zone 7a (0º F minimum) in Benton and Franklin Counties

  • Zones range from 6a to 7a (-10 to 0º F minimum) in Yakima County

Precipitation (click for map)


  • Hot, dry and sunny.

  • July-August temperatures reach into the 90's, often exceeding 100º F for a few days.

Frost Days

  • Growing season is approximately mid-April to mid-October.


  • Generally alkaline (pH > 7).