One of the first steps you take when you are figuring out your gardening schedule is find your 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 using the USDA zone info for Roma you will be able to figure out when you can 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 Roma is January. However, you really should wait until February 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 October. You probably don't want to wait any later than that or else your bok choi may not have a chance to fully mature. 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

The average date of last frost is February 15 in Roma. You should expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Roma is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Roma it frosts late in the year after February 15 be ready to cover your bok choi if you have a late frost.

USDA Zone Info for Roma

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

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

Plants to Grow in Roma

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