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

The USDA zone info for Petersburg can be reffered to in order to determine when it's possible to plant schizanthus.

Planting Calendar for Schizanthus

Frost tolerance for schizanthus:	Not tolerant of frost.
When to plant:	After the last frost.

It's probably a bad idea to plant schizanthus until after the last frost when the weather gets warmer because they are not cold tolerant.

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

The last month that you can plant schizanthus and expect a good harvest is probably August. You probably don't want to wait any later than that or else your schizanthus may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your schizanthus indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Petersburg. It might get as low as 5°F during the coldest months of winter.

Since the USDA zone info for Petersburg is not always accurate the actual date of last frost is different every year. Since half of the time in Petersburg you get surprised by a frost after April 15 be ready to cover your schizanthus if you have a 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.