Before planting it is a good idea to find your USDA Zone info to figure out 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.

It's possible to determine when to plant purple rock cress by referring to the USDA zone info for Carnegie.

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.

You can plant purple rock cress a lot earlier in the year because they are one of those plants that can tolerate quite a bit of cold weather.

The earliest that you can plant purple rock cress in Carnegie 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. Any later than that and your purple rock cress may not have a chance to grow to maturity. 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

The average date of last frost is April 15 in Carnegie. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Carnegie is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in Carnegie you get a frost after April 15 so just be sure to be ready to protect your purple rock cress in the event of a surprise late frost.

USDA Zone Info for Carnegie

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 Carnegie

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