The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to figure out when you can plant arabis by reviewing the USDA zone info for Washington.

Planting Calendar for Arabis

Frost tolerance for arabis:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Arabis do well in cold which tells us that you can start planting them much earlier than other frost tender plants.

The earliest that you can plant arabis in Washington is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant arabis and expect a good harvest is probably September. You probably don't want to wait any later than that or else your arabis may not have a chance to grow to maturity. If you are starting your arabis indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Washington. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Washington is an average the actual date of last frost will vary from year to year. Half of the time in Washington it frosts late in the year after April 15 so always be ready to protect your arabis if you have a surprise late frost.

USDA Zone Info for Washington

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Washington

You may be interested in your other planting guides for Washington.