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.

The USDA zone info for Sonoma should be reviewed to estimate when it's the best time 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.

Oenothera are moderately cold tolerant which means that you can plant them a little bit earlier than other plants that might not handle the cold.

The earliest that you can plant oenothera in Sonoma is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant oenothera and expect a good harvest is probably October. You probably don't want to wait any later than that or else your oenothera may not have a chance to grow to maturity. If you are starting your oenothera indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost is on February 15 in Sonoma. You should expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Sonoma may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Sonoma last frost occurs after February 15 so just be sure to be ready to cover your oenothera if you have a surprise late frost.

USDA Zone Info for Sonoma

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Sonoma

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