Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of determining when to plant rock cress is to use the USDA zone info for Ionia.

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 do well in cold you can plant them much earlier in the year than more sensitive plants.

The earliest that you can plant rock cress in Ionia 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. Starting your rock cress indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Ionia. It might get as low as -15°F during the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Ionia and it can change quite a bit from year to year. Half of the time in Ionia last frost occurs after April 15 so make sure that you are prepared to protect your rock cress in the event of one of those late frosts.

USDA Zone Info for Ionia

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 Ionia

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