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.

The earliest that you can plant primula in Washington can be determined 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 much earlier in the year than more sensitive 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 grow to maturity. You can get started a couple of weeks earlier by starting your primula indoors.

Last Frost Date

On average the last frost has passed is on March 15 in Washington. It might get as low as 10°F during the coldest months of winter.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Washington and it will vary from year to year. Half of the time in Washington last frost occurs after March 15 so make sure that you are prepared to cover your primula if you have a surprise late frost.

USDA Zone Info for Washington

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Washington

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