One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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 estimate when it's possible to plant bok choi by using the USDA zone info for Petersburg.

Planting Calendar for Bok Choi

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

Since bok choi are moderately cold tolerant you can plant them just a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant bok choi 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 bok choi and expect a good harvest is probably September. Any later than that and your bok choi may not have a chance to fully mature. You can get started a few weeks earlier by starting your bok choi indoors.

Last Frost Date

On average the last frost is on April 15 in Petersburg. In the coldest months of winter you should expect an average low temperature of 5°F.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Petersburg and it changes from year to year. Half of the time in Petersburg you get a frost after April 15 so be sure to be ready to protect your bok choi in the event of one of those late frosts.

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.