Before planting it is a good idea to find your USDA Zone info to estimate 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.

By reviewing the USDA zone info for International Falls you should be able to determine when it's possible to 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 do well in moderate cold which tells us that you can plant them a little bit earlier than other frost tender plants.

The earliest that you can plant bok choi in International Falls is March. However, you really should wait until April 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 August. Any later than that and your bok choi may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your bok choi indoors.

Last Frost Date

On average the last frost has passed is on May 15 in International Falls. In the coldest months of winter you should expect an average low temperature of -40°F.

Since the USDA zone info for International Falls is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in International Falls it frosts late in the year after May 15 be ready to protect your bok choi in the event of one of those late frosts.

USDA Zone Info for International Falls

Here is the info for USDA Zone 3a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-40°F
Highest Expected Low	-35°F

This means that on a really cold year, the coldest it will get is -40°F. On most years you should be prepared to experience lows near -35°F.

Plants to Grow in International Falls

You may be interested in your other planting guides for International Falls.