The USDA Zone info is a great tool for gardeners to help us estimate 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.

A way of determining when it's possible to plant primula is to look at the USDA zone info for Forest Grove.

Planting Calendar for Primula

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

Primula do well in pretty solid cold which tells us that you can plant them quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant primula in Forest Grove 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. If you wait any later than that and your primula may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your primula indoors.

Last Frost Date

In Forest Grove the average date of last frost happens on March 15. It might get as low as 15°F during the coldest months of winter.

Since the USDA zone info for Forest Grove is not always accurate the actual date of last frost changes from year to year. Since half of the time in Forest Grove last frost occurs after March 15 be ready to protect your primula if you have a late frost.

USDA Zone Info for Forest Grove

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 Forest Grove

You may be interested in your other planting guides for Forest Grove.