The USDA Zone info is a great tool for gardeners to help us determine 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 earliest that you can plant rock cress in Granite City can be figured out by reviewing the USDA zone info.

Planting Calendar for Rock Cress

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

Rock Cress do well in cold which tells us that you can start planting them much earlier than more sensitive plants.

The earliest that you can plant rock cress in Granite City 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. If you wait any later than that and your rock cress may not have a chance to really do well. You can get started a few weeks earlier by starting your rock cress indoors.

Last Frost Date

The average date of last frost is April 15 in Granite City. In the coldest months of winter you should expect an average low temperature of -5°F.

Since the USDA zone info for Granite City may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Granite City you get a frost after April 15 so just be sure to be ready to protect your rock cress in the event of a surprise late frost.

USDA Zone Info for Granite City

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 Granite City

You may be interested in your other planting guides for Granite City.