One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to figure out when it's a good idea to plant purple rock cress by reviewing the USDA zone info for Williamsburg.

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.

Purple Rock Cress are very cold tolerant which means that you can start planting them much earlier than plants that are more sensitive to the cold.

The earliest that you can plant purple rock cress in Williamsburg 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. If you wait any later than that and 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 little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Williamsburg. You can expect an average low temperature of 5°F in the coldest months of winter.

Since the USDA zone info for Williamsburg is an average the actual date of last frost is different every year. Half of the time in Williamsburg there is a last frost after April 15 so make sure that you are prepared to cover your purple rock cress if you have one of those late frosts.

USDA Zone Info for Williamsburg

Here is the info for USDA Zone 7b.

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

Plants to Grow in Williamsburg

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