One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By referring to the USDA zone info for Commerce it's possible to estimate when it's a good idea to plant purple rock cress.

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.

You can plant purple rock cress much earlier in the year because they are very cold tolerant.

The earliest that you can plant purple rock cress in Commerce 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 purple rock cress and expect a good harvest is probably September. If you wait any later than that and your purple rock cress may not have a chance to fully mature. You can get started a few weeks earlier by starting your purple rock cress indoors.

Last Frost Date

In Commerce the average date of last frost happens on March 15. It might get as low as 10°F during the coldest months of winter.

Since the USDA zone info for Commerce is just an average the actual date of last frost will vary from year to year. Half of the time in Commerce you get surprised by a frost after March 15 so make sure that you are ready to protect your purple rock cress if you have one of those late frosts.

USDA Zone Info for Commerce

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Commerce

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