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.

By referring to the USDA zone info for Cambridge you will be able to estimate when 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.

Since bok choi 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 bok choi in Cambridge 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 really do well. You can get started a couple of weeks earlier by starting your bok choi indoors.

Last Frost Date

On average all chance of frost has passed is on May 15 in Cambridge. In the coldest months of winter you should expect an average low temperature of -30°F.

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 Cambridge and it changes from year to year. Half of the time in Cambridge there is a last frost after May 15 so make sure that you are prepared to protect your bok choi in the event of one of those late frosts.

USDA Zone Info for Cambridge

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Cambridge

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