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Coronavirus COVID-19

COVID-19 Advisory: WSU Extension is working to keep our communities safe. All Extension programming is being provided virtually, postponed, or canceled. Effective March 16, 2020, WSU Extension county offices and WSU Research & Extension Centers will be closed to the public. We are available via email, phone, and webconference.


Program Contact: Nan Doolittle, Master Gardener Coordinator
(509) 962-7507 •

General Gardening Information
USDA Plant Zones
  • Cle Elum is in Zone 4 (-30ºF minimum temperature)
  • Ellensburg is in Zone 5 (-20ºF minimum temperature)
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.