One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Petaluma can be looked at 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.

You can plant bok choi just a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant bok choi in Petaluma 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 fully mature. Starting your bok choi indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on February 15 in Petaluma. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Petaluma is just an average the actual date of last frost will vary from year to year. Half of the time in Petaluma there is a last frost after February 15 so always be ready to protect your bok choi in the event of a late frost.

USDA Zone Info for Petaluma

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 Petaluma

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