Before planting it is a good idea to find your USDA Zone info to figure out 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.

The earliest that you can plant rock cress in Palo Alto should be estimated by looking at 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.

Since rock cress are very cold tolerant you can plant them much earlier in the year than other plants that might not handle the cold.

The earliest that you can plant rock cress in Palo Alto 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. Any later than that and your rock cress may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your rock cress indoors.

Last Frost Date

The average date of last frost is February 15 in Palo Alto. In the coldest months of winter you should expect an average low temperature of 25°F.

Since the USDA zone info for Palo Alto may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Palo Alto you get a frost after February 15 so just be sure to be ready to protect your rock cress in the event of a late frost.

USDA Zone Info for Palo Alto

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 Palo Alto

You may be interested in your other planting guides for Palo Alto.