The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. 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 Holly should be reviewed to determine when you can 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 can survive in quite a bit of cold which means that you can plant them quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant rock cress in Holly 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. You probably don't want to wait any later than that or else your rock cress may not have a chance to grow to maturity. Starting your rock cress indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Holly. In the coldest months of winter you should expect an average low temperature of -10°F.

Just be sure to remember that USDA zone info for Holly is an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Holly you get surprised by a frost after April 15 be ready to cover your rock cress in the event of a late frost.

USDA Zone Info for Holly

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Holly

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