Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. 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 Philadelphia should be reviewed to estimate when you can plant bok choi.

Planting Calendar for Bok Choi

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

Bok Choi can survive in some cold which tells us that you can plant them a little bit earlier in the year than other frost tender plants.

The earliest that you can plant bok choi in Philadelphia 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. If you wait 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

The average date of last frost is April 15 in Philadelphia. It might get as low as 0°F during the coldest months of winter.

Since the USDA zone info for Philadelphia is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Philadelphia last frost occurs after April 15 so just be sure to be ready to cover your bok choi in the event of a surprise late frost.

USDA Zone Info for Philadelphia

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Philadelphia

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