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.

It's possible to determine when it's possible to plant sweet williams by using the USDA zone info for Petersburg.

Planting Calendar for Sweet Williams

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

Since sweet williams do well in moderate cold you can plant them a little earlier in the year than other plants that might not handle the cold.

The earliest that you can plant sweet williams 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 sweet williams and expect a good harvest is probably September. You probably don't want to wait any later than that or else your sweet williams may not have a chance to really do well. You can get started a couple of weeks earlier by starting your sweet williams indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Petersburg. You can expect an average low temperature of 5°F in the coldest months of winter.

Always keep in mind that USDA zone info for Petersburg is an average and the actual date of last frost will vary from year to year. Since half of the time in Petersburg last frost occurs after April 15 be ready to protect your sweet williams 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.