The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Aspen should be reffered to in order to estimate when 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.

Purple Rock Cress are one of those plants that can tolerate quite a bit of cold weather which means that you can start planting them much earlier than other plants that might not handle the cold.

The earliest that you can plant purple rock cress in Aspen 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. 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

The average date of last frost is April 15 in Aspen. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Aspen is just an average the actual date of last frost changes from year to year. Half of the time in Aspen last frost occurs after April 15 so be sure to be ready to protect your purple rock cress if you have one of those late frosts.

USDA Zone Info for Aspen

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

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

Plants to Grow in Aspen

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