One of the first steps you take when you are determining 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.

In Chicago Ridge you can estimate when to plant purple rock cress 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.

Purple Rock Cress are very cold tolerant which means that you can get them planted much earlier than more sensitive plants.

The earliest that you can plant purple rock cress in Chicago Ridge 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. If you are starting your purple rock cress indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Chicago Ridge the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -10°F.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Chicago Ridge and it changes from year to year. Since half of the time in Chicago Ridge there is a last frost after April 15 be ready to cover your purple rock cress in the event of one of those late frosts.

USDA Zone Info for Chicago Ridge

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°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 -5°F.

Plants to Grow in Chicago Ridge

You may be interested in your other planting guides for Chicago Ridge.