One of the first steps you take when you are determining 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.

You can determine when it's the best time to plant primula in Washington by using the USDA zone info.

Planting Calendar for Primula

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

Since primula do well in cold you can plant them earlier in the year than plants that are more sensitive to the cold.

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. You probably don't want to wait any later than that or else your primula may not have a chance to really do well. Starting your primula indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Washington. In the coldest months of winter you should expect an average low temperature of -5°F.

Since the USDA zone info for Washington is an average the actual date of last frost changes from year to year. Since half of the time in Washington last frost occurs after April 15 be ready to cover your primula if you have a surprise late frost.

USDA Zone Info for Washington

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Washington

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