One of the best tools that you have as gardeners to help us estimate 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.

A way of making a decision about when it's the best time to plant oenothera is to use the USDA zone info for Dayton.

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 just a bit earlier in the year because they do well in moderate cold.

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

The last month that you can plant oenothera and expect a good harvest is probably August. You probably don't want to wait any later than that or else your oenothera may not have a chance to really do well. 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 has passed is on May 15 in Dayton. In the coldest months of winter you can expect an average low temperature of -25°F.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Dayton and it changes from year to year. Since half of the time in Dayton you get surprised by a frost after May 15 be ready to cover your oenothera in the event of one of those late frosts.

USDA Zone Info for Dayton

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°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 -20°F.

Plants to Grow in Dayton

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