One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Harrisburg should be reffered to in order to determine when it's a good idea 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.

You can plant rock cress 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 rock cress in Harrisburg 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 grow to maturity. Starting your rock cress indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Harrisburg. You can expect an average low temperature of 0°F in the coldest months of winter.

Since the USDA zone info for Harrisburg is not always accurate the actual date of last frost changes from year to year. Since half of the time in Harrisburg there is a last frost after April 15 be ready to cover your rock cress in the event of a late frost.

USDA Zone Info for Harrisburg

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Harrisburg

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