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

It's possible to determine when you can plant oenothera by reviewing the USDA zone info for Grass Valley.

Planting Calendar for Oenothera

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

Since oenothera are one of those plants that can tolerate a little bit of cold weather you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant oenothera in Grass Valley 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 really do well. Starting your oenothera indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is February 15 in Grass Valley. You should expect an average low temperature of 20°F in the coldest months of winter.

Since the USDA zone info for Grass Valley is an average the actual date of last frost changes from year to year. Half of the time in Grass Valley last frost occurs after February 15 so be sure to be ready to cover your oenothera in the event of a surprise late frost.

USDA Zone Info for Grass Valley

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Grass Valley

You may be interested in your other planting guides for Grass Valley.