One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Zone 5b should be reviewed to estimate when 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.

Rock Cress tend to make it in quite a bit of cold which tells us that you can plant them earlier in the year than other frost tender plants.

The earliest that you can plant rock cress in Zone 5b 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 grow to maturity. If you are starting your rock cress indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Zone 5b the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Zone 5b and it will vary from year to year. Half of the time in Zone 5b there is a last frost after April 15 so always be ready to cover your rock cress in the event of a surprise late frost.

USDA Zone Info for Zone 5b

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 Zone 5b

You may be interested in your other planting guides for Zone 5b.