Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In National City you can figure out when it's possible to plant rock cress by checking out the USDA zone info.

Planting Calendar for Rock Cress

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

Rock Cress are very cold tolerant which tells us that you can get them planted much earlier than more sensitive plants.

The earliest that you can plant rock cress in National City 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 rock cress and expect a good harvest is probably October. You probably don't want to wait any later than that or else your rock cress may not have a chance to really do well. You can get started a few weeks earlier by starting your rock cress indoors.

Last Frost Date

On average the last frost is on January 31 in National City. You should expect an average low temperature of 35°F in the coldest months of winter.

Since the USDA zone info for National City is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in National City it frosts late in the year after January 31 so be sure to be ready to protect your rock cress in the event of one of those late frosts.

USDA Zone Info for National City

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in National City

You may be interested in your other planting guides for National City.