One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of determining when it's possible to plant oenothera is to consult the USDA zone info for Ripon.

Planting Calendar for Oenothera

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

Oenothera are one of those plants that can tolerate a little bit of cold weather which tells us that you can start planting them earlier than plants that are more sensitive to the cold.

The earliest that you can plant oenothera in Ripon 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. Any later than that and your oenothera may not have a chance to really do well. You can get started a little bit earlier by starting your oenothera indoors.

Last Frost Date

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

Since the USDA zone info for Ripon may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Ripon you get surprised by a frost after February 15 be ready to cover your oenothera if you have a surprise late frost.

USDA Zone Info for Ripon

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 Ripon

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