Washington Planting Zones

Washington state is home to an incredibly diverse climate. The region stretches across six different planting zones (4, 5, 6, 7, 8, and 9), and the annual minimum temperature sits between -30° and 25° F (-34.4° and -3.9° C) across the state.

In this article, you will learn:


The terrain of Washington is spectacular and varies dramatically throughout the region. The landscape is made up of rugged coastlines, temperate rainforests, towering mountains and volcanoes, and rolling hills. While the region is breathtaking, gardeners may experience a range of difficulties depending on what area of the state you’re located in.

Image from USDA

Characteristics of Washington Planting Region

Washington state can be divided into two distinct climate regions:

  • Western Region
  • This part of the state experiences mild, humid summer days and very mild winters. Snow is quite rare outside of the mountainous region, but rainfall, clouds, and fog are common across the entire area.

  • Eastern Region
  • The eastern part of the state will experience much hotter summers and considerably colder winters than the western region. Rainfall is minimal, while sunshine is consistent throughout the year.

    Additionally, much of the state can be subjected to extreme events such as wildfires, flooding, severe storms, landslides, and even earthquakes.

    The growing season varies dramatically across the region, so it’s best to find the specific frost-free dates for your area before getting started.

    Hurricane Ridge Olympic National Park, Washington, USA

    Challenges of Growing in Washington

    1. Diverse Climate

    The diversity of Washington’s climate means temperatures and frost dates can vary drastically throughout short distances across the state. Regardless of what zone or region you’re located in, many choose to use protective coverings combined with indoor growing to avoid disappointment brought on by late or early frosts.

    2. Extreme Weather

    Severe storms, flooding, and wildfires can all be detrimental to your garden’s success. While many of these events are beyond our control, it’s suggested to use raised garden beds and protective coverings to keep your hard work out of harm’s way.

    The Benefits of Using a Greenhouse in Washington

    There are a multitude of benefits to using a greenhouse in the state of Washington. Extended growing seasons, protection from extreme weather events, and avoiding damage from unexpected frosts are just a few advantages to greenhouse growing in this region. Not to mention, gardeners will be able to grow a much wider variety of vegetables without the need to transplant them at a later date.

    1. Extend your Growing Season

    • Without a Greenhouse:
      The average growing season can vary wildly across the state. While the lower altitude and coastal areas can experience 5-7 months of growing time, most of the state is limited to 3-4 months. Regardless of what area you’re located in, early frosts and mild weather still make growing many vegetables a challenge. 

    • With a Greenhouse:
      Using a greenhouse in Washington will allow you to extend your growing season to at least 8-9 months for those who live inland and potentially allow coastal gardeners to plant year-round. However, due to the high-intensity sunshine in the eastern regions, many gardeners throughout the rest of the state may also be able to experiment with year-long growing.

    Learn more about specific growing dates for your area and the best vegetables to plant in each part of Washington.


    Customer images of greenhouse growing in a similar climate

    2. Grow a Wider Variety of Vegetables 

    • Without a Greenhouse:
      Many warm-season or slow-maturing plants may struggle to survive in most parts of Washington. Even in warmer coastal areas, there is a danger of late/early frosts damaging your garden. The following are some cold-hardy vegetables that can survive through cooler dips and surprise frosts:
    • Broccoli
    • Beets
    • Kale
    • Spinach
    • Peas
    • Turnips
    • Radish
    • Endive


    • With a Greenhouse:
      A greenhouse will allow gardeners in Washington to plant a much wider variety of vegetables and experiment with many long-season and warm weather crops. Some of the vegetables known to flourish in a greenhouse in this region include:
    • Beans
    • Brussel Sprouts
    • Tomatoes
    • Cucumbers
    • Eggplants
    • Summer Squash
    • Melons
    • Carrots
    • Potatoes
    • Cauliflower
    • Onions
    • Sweet Peppers
    • Pumpkins
    • Winter Squash
    • Artichokes
    • Asparagus
    • Corn
    • Garlic
    • Lettuce
    • Hot Peppers
    • Parsley
    • Cherry Tomatoes
    • Okra
    • Swiss Chard
    • Rosemary
    • Parsnips
    • Oregano


    Tomatoes growing in a greenhouse

    Why Planta Greenhouses?

    Customer Stories From Washington

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