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Program Contact: Patty Ratzlaff, Master Gardener Coordinator
(509) 962-7507 •

General Gardening Information

USDA Plant Zones

  • USDA Zone 6a (-10 to -5 F) and 6b (-5 to 0 F) for most of Kittitas County.  Hardiness zones or planting zones have large boundaries and may not be exact enough for your site, zones grade into and out of each other gradually and irregularly. Rely on your own experience in your garden. Also consider the effect of your elevation upon your specific situation.

Growing season averages

  • 120 days in lower county
  • 90-120 days in upper county


  • Ellensburg 1,520 feet
  • Cle Elum 1,930 feet

Precipitation, annual average

  • Easton: 53.5″
  • Cle Elum: 37.2″
  • Ellensburg: 9″
  • Vantage: 6.9″


Average last spring frost
  • Ellensburg: May 1
  • Cle Elum: May 24
Average first fall frost
  • Ellensburg: September 25
  • Cle Elum: September 11


Out of the west and Northwest. The strongest winds come in late spring, decreasing in the summer months. Wind flow should be taken into consideration when planning your planting beds and garden.

Lawn Seed

Mixes of bluegrass and fine-leaf fescues make superior quality lawns and are best suited for our area.


Alkaline-soils tend to be on the higher side of the pH scale. A list of soil testing labs is available from our office.

Kittitas County Master Gardener YouTube Channel