One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant purple rock cress in Larkspur should be figured out by referring to the USDA zone info.

Planting Calendar for Purple Rock Cress

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

Since purple rock cress do well in cold you can plant them a lot earlier in the year than more sensitive plants.

The earliest that you can plant purple rock cress in Larkspur 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 purple rock cress and expect a good harvest is probably October. Any later than that and your purple rock cress may not have a chance to really do well. Starting your purple rock cress indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Larkspur the average date of last frost happens on February 15. You should expect an average low temperature of 25°F in the coldest months of winter.

It's important to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Larkspur and it changes from year to year. Since half of the time in Larkspur it frosts late in the year after February 15 be ready to cover your purple rock cress if you have one of those late frosts.

USDA Zone Info for Larkspur

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 Larkspur

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