One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Washington you can figure out when to plant primroses by using the USDA zone info.

Planting Calendar for Primroses

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

Since primroses are very cold tolerant you can plant them quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant primroses 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 primroses and expect a good harvest is probably September. If you wait any later than that and your primroses may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your primroses indoors.

Last Frost Date

The average date of last frost is April 15 in Washington. In the coldest months of winter you can expect an average low temperature of -15°F.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Washington and it will vary from year to year. Since half of the time in Washington last frost occurs after April 15 be ready to protect your primroses in the event of one of those late frosts.

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.