The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to figure out when it's the best time to plant bok choi by using the USDA zone info for Napa.

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 are moderately cold tolerant which means that you can start planting them earlier than more sensitive plants.

The earliest that you can plant bok choi in Napa 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. Any later than that and your bok choi may not have a chance to really do well. 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 Napa. You can expect an average low temperature of 25°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Napa and it is different every year. Since half of the time in Napa you get a frost after February 15 be ready to cover your bok choi if you have a surprise late frost.

USDA Zone Info for Napa

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 Napa

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