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.

A way of figuring out when to plant primula is to examine the USDA zone info for Tualatin.

Planting Calendar for Primula

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

You can plant primula earlier in the year because they do well in cold.

The earliest that you can plant primula in Tualatin 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 fully mature. You can get started a few weeks earlier by starting your primula indoors.

Last Frost Date

In Tualatin the average date of last frost happens on March 15. In the coldest months of winter you should expect an average low temperature of 15°F.

It's important to remember that USDA zone info for Tualatin is just an average and the actual date of last frost will vary from year to year. Since half of the time in Tualatin there is a last frost after March 15 be ready to protect your primula in the event of one of those late frosts.

USDA Zone Info for Tualatin

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Tualatin

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