One of the first steps you take when you are figuring out 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 best time to plant rock cress in California can be estimated by using 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 one of those plants that can tolerate quite a bit of cold weather which tells us that you can start planting them much earlier than other frost tender plants.

The earliest that you can plant rock cress in California is February. However, you really should wait until March 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 September. Any later than that and your rock cress may not have a chance to fully mature. You can get started a little bit earlier by starting your rock cress indoors.

Last Frost Date

In California the average date of last frost happens on April 15. You can expect an average low temperature of -5°F in the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for California and it can change quite a bit from year to year. Since half of the time in California last frost occurs after April 15 be ready to protect your rock cress in the event of a surprise late frost.

USDA Zone Info for California

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in California

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