One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Troutdale can be looked at to figure out when it's a good idea to plant primula.

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 cold which tells us that you can plant them a quite a bit earlier than plants that are more sensitive to the cold.

The earliest that you can plant primula in Troutdale 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. If you are starting your primula indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Troutdale and it can change quite a bit from year to year. Since half of the time in Troutdale 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 Troutdale

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 Troutdale

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