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.

One way of figuring out when it's a good idea to plant erysimum is to examine the USDA zone info for Jefferson.

Planting Calendar for Erysimum

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

You can plant erysimum just a bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

The earliest that you can plant erysimum in Jefferson 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 erysimum and expect a good harvest is probably September. You probably don't want to wait any later than that or else your erysimum may not have a chance to fully mature. You can get started a few weeks earlier by starting your erysimum indoors.

Last Frost Date

The average date of last frost is April 15 in Jefferson. In the coldest months of winter you should expect an average low temperature of -20°F.

Since the USDA zone info for Jefferson is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in Jefferson there is a last frost after April 15 so make sure that you are prepared to cover your erysimum if you have a surprise late frost.

USDA Zone Info for Jefferson

Here is the info for USDA Zone 5a.

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

Plants to Grow in Jefferson

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