One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to determine when it's the best time to plant bok choi by looking at the USDA zone info for Romulus.

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 some cold which tells us that you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant bok choi in Romulus 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 grow to maturity. Starting your bok choi indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Romulus the average date of last frost happens on April 15. It might get as low as -10°F during the coldest months of winter.

Since the USDA zone info for Romulus is not always accurate the actual date of last frost is different every year. Half of the time in Romulus you get surprised by a frost after April 15 so always be ready to protect your bok choi in the event of one of those late frosts.

USDA Zone Info for Romulus

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Romulus

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