One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to determine when to plant erysimum by looking at the USDA zone info for Petersburg.

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 moderately cold tolerant.

The earliest that you can plant erysimum in Petersburg 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. If you wait any later than that and your erysimum may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your erysimum indoors.

Last Frost Date

The average date of last frost is April 15 in Petersburg. In the coldest months of winter you can expect an average low temperature of 5°F.

Since the USDA zone info for Petersburg may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Petersburg you get a frost after April 15 be ready to protect your erysimum in the event of a surprise late frost.

USDA Zone Info for Petersburg

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°F

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Petersburg

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