Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of estimating when it's possible to plant purple rock cress is to look at the USDA zone info for Frankfort.

Planting Calendar for Purple Rock Cress

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

Since purple 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 purple rock cress in Frankfort 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 purple rock cress and expect a good harvest is probably September. You probably don't want to wait any later than that or else your purple rock cress may not have a chance to really do well. If you are starting your purple rock cress indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Frankfort the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -15°F.

Since the USDA zone info for Frankfort is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Frankfort last frost occurs after April 15 be ready to cover your purple rock cress if you have a late frost.

USDA Zone Info for Frankfort

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 Frankfort

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