Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. 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 Seattle can be read to estimate when it's possible to plant oenothera.

Planting Calendar for Oenothera

Frost tolerance for oenothera:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant oenothera a little bit earlier in the year because they do well in moderate cold.

The earliest that you can plant oenothera in Seattle 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 oenothera and expect a good harvest is probably September. You probably don't want to wait any later than that or else your oenothera may not have a chance to really do well. You can get started a couple of weeks earlier by starting your oenothera indoors.

Last Frost Date

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

Keep in mind that USDA zone info for Seattle is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Seattle last frost occurs after March 15 so be sure to be ready to protect your oenothera in the event of one of those late frosts.

USDA Zone Info for Seattle

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 Seattle

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