The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. 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 Colusa should be used to determine 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.

Bok Choi do well in moderate cold which means that you can start planting them earlier than more sensitive plants.

The earliest that you can plant bok choi in Colusa 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. If you wait any later than that and your bok choi may not have a chance to really do well. Starting your bok choi indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost is on February 15 in Colusa. In the coldest months of winter you should expect an average low temperature of 25°F.

Since the USDA zone info for Colusa is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Colusa last frost occurs after February 15 so make sure that you are ready to protect your bok choi if you have one of those late frosts.

USDA Zone Info for Colusa

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 Colusa

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