The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The earliest that you can plant bok choi in Zone 1a should be determined by using the USDA zone info.

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 tend to make it in moderate cold which means that you can plant them a little earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant bok choi in Zone 1a is May. However, you really should wait until June 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 July. You probably don't want to wait any later than that or else your bok choi may not have a chance to grow to maturity. Starting your bok choi indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost is on June 15 in Zone 1a. You should expect an average low temperature of -60°F in the coldest months of winter.

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Zone 1a and it can change quite a bit from year to year. Since half of the time in Zone 1a it frosts late in the year after June 15 be ready to protect your bok choi if you have one of those late frosts.

USDA Zone Info for Zone 1a

Here is the info for USDA Zone 1a.

Average Date of Last Frost (spring)	June 15
Average Date of First Frost (fall)	July 15
Lowest Expected Low	-60°F
Highest Expected Low	-55°F

This means that on a really cold year, the coldest it will get is -60°F. On most years you should be prepared to experience lows near -55°F.

Plants to Grow in Zone 1a

You may be interested in your other planting guides for Zone 1a.