The USDA Zone info is a great tool for gardeners to help us determine 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 Harvard can be estimated by checking out 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.

Since bok choi are moderately cold tolerant 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 Harvard 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. 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. If you are starting your bok choi indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Harvard the average date of last frost happens on April 15. You should expect an average low temperature of -15°F in the coldest months of winter.

It's important to remember that USDA zone info for Harvard is just an average and the actual date of last frost will vary from year to year. Half of the time in Harvard it frosts late in the year after April 15 so make sure that you are prepared to cover your bok choi in the event of one of those late frosts.

USDA Zone Info for Harvard

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Harvard

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