One of the best tools that you have as gardeners to help us figure out 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 USDA zone info for Herrin can be reviewed to figure out when it's the best time to plant rock cress.

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 a lot earlier in the year than plants that are more sensitive to the cold.

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

Last Frost Date

The average date of last frost is April 15 in Herrin. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Herrin is not always accurate the actual date of last frost will vary from year to year. Half of the time in Herrin last frost occurs after April 15 so make sure that you are ready to protect your rock cress in the event of one of those late frosts.

USDA Zone Info for Herrin

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Herrin

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