The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of estimating when it's possible to plant rock cress is to use the USDA zone info for Winthrop Harbor.

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 tend to make it in a bit of cold which means that you can plant them a lot earlier in the year than other frost tender plants.

The earliest that you can plant rock cress in Winthrop Harbor 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 fully mature. You can get started a couple of weeks earlier by starting your rock cress indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Winthrop Harbor. In the coldest months of winter you should expect an average low temperature of -15°F.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Winthrop Harbor and it will vary from year to year. Half of the time in Winthrop Harbor you get surprised by a frost after April 15 so make sure that you are prepared to cover your rock cress if you have one of those late frosts.

USDA Zone Info for Winthrop Harbor

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 Winthrop Harbor

You may be interested in your other planting guides for Winthrop Harbor.