Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of determining when it's the best time to plant bok choi is to look at the USDA zone info for San Mateo.

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 can survive in mild cold which means that you can plant them a little bit earlier in the year than more sensitive plants.

The earliest that you can plant bok choi in San Mateo 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. You can get started a little bit earlier by starting your bok choi indoors.

Last Frost Date

On average all chance of frost has passed is on January 31 in San Mateo. It might get as low as 30°F during the coldest months of winter.

Just be sure to remember that USDA zone info for San Mateo may not be accurate from year to year and the actual date of last frost will vary from year to year. Half of the time in San Mateo last frost occurs after January 31 so always be ready to cover your bok choi if you have one of those late frosts.

USDA Zone Info for San Mateo

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in San Mateo

You may be interested in your other planting guides for San Mateo.