Washington Hardiness Zones: 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a
Washington is known for its high yearly rainfall and lush green forests. The state is covered by a wide range of geographical regions, like coastal towns, mountain ranges, volcanic peaks, lowlands and plateaus. Because of this, Washington has a wide range of growing hardiness zones all the way from 4a to 9a.
The west of the state tends to remain between 50 and 80 degrees year round and receives 200 inches of precipitation per year, while the east has warmer summers and cooler winters and only 6 inches of precipitation annually.
A hot summer day in the east can reach highs of 90, while the winter gets as low as 30 with snowfall. Summers tend to be drier, while the fall and winter months have the highest number of days with rain.
- If you live along the coast you are likely in hardiness zone 9a. This area of the state remains between 50 to 80 degrees year round.
- The area further east off the coast moves to a zone 8
- Small areas of the state along the Cascade Mountain range are in zones 4a, 4b, 5a and 5b. It is important to find these on the map because the areas immediately surrounding them can be from 6a to 8a
- The north of the state as well as the areas around Lincoln and Spokane (which are both zone 6b) are in hardiness zone 6a, with much of the rest of the state being zone 6b or 7a
Above you can find the Washington hardiness zones map, sometimes called the growing zones map based on the 2012 USDA map data. This map provides gardeners and farmers with the information they need to decipher what plants will grow best in their region and what their optimal growing time is.
To use the map, begin by finding your area on the map. You can also search by zip code. See the color of your area and compare that to the legend. The legend will tell you what your hardiness zone is.
Washington is primarily in zones 6a through 9a however, the hardiness map is very important because there are a few small pockets of the state that get as low as zone 4a. This will help you to decide what plants you can grow outdoors.
This information from the USDA is just a guide. It is also important to discuss with greenhouses and nurseries what plants will thrive in your area. Use planting and care instructions as a guideline and remember that you can always move plants indoors to help them survive winter.
You can create something called a micro-climate in your yard. This happens when your yard has artificial replicas of naturally occurring geographical climates, such as a pond, large rocks, or treelines. This can change the hardiness zone of your yard, one zone up or down.
To create a more friendly yard for growing, plant trees or large shrubs around the edges of your yard.
Most of Washington tends to have a long growing season. Planting can begin in many areas in March and the first frost of the fall usually doesn’t hit until late in November. According to Watson’s Greenhouse the long season and warm weather allow for you to grow a great selection of fruits and vegetables.
Choose options like root vegetables, greens, fruit trees or berries. Keep in mind the west coast has primarily overcast days and not a lot of direct sunlight.
If you live in one of the small areas that are in zones 4a through 5b, your growing season will be much shorter. You can manage this by creating a micro-climate in your yard with large rocks to help produce heat and by starting vegetables that take longer to mature inside before the last melt of the spring has hit.
Starting vegetables indoors in March and transferring them outside after they have started is a great way to ensure they have ample time to fully mature.
Provided that you consider your hardiness growing zone and carefully follow planting care and instructions, you can grow a beautiful and successful garden in Washington.