The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to determine when it's a good idea to plant primula by using the USDA zone info for Washington.

Planting Calendar for Primula

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

Since primula are one of those plants that can tolerate quite a bit of cold weather you can plant them quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant primula 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 primula and expect a good harvest is probably September. Any later than that and your primula may not have a chance to really do well. You can get started a couple of weeks earlier by starting your primula indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Washington. You can expect an average low temperature of -10°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. Since half of the time in Washington it frosts late in the year after April 15 be ready to protect your primula in the event of a surprise late frost.

USDA Zone Info for Washington

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Washington

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