One of the first steps you take when you are determining 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.

By checking out the USDA zone info for San Diego it's a good idea to estimate when it's the best time to plant napa cabbage.

Planting Calendar for Napa cabbage

Frost tolerance for napa cabbage:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Napa cabbage can survive in cold weather which means that you can plant them earlier in the year than other frost tender plants.

The earliest that you can plant napa cabbage in San Diego 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 napa cabbage and expect a good harvest is probably October. Any later than that and your napa cabbage may not have a chance to really do well. If you are starting your napa cabbage indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost has passed is on February 15 in San Diego. In the coldest months of winter you should expect an average low temperature of 20°F.

Since the USDA zone info for San Diego is just an average the actual date of last frost is different every year. Half of the time in San Diego it frosts late in the year after February 15 so make sure that you are ready to protect your napa cabbage if you have one of those late frosts.

USDA Zone Info for San Diego

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in San Diego

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