Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of determining when it's the best time to plant purple rock cress is to look at the USDA zone info for Zone 8b.

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 one of those plants that can tolerate quite a bit of cold weather which tells us that you can plant them a quite a bit earlier than more sensitive plants.

The earliest that you can plant purple rock cress in Zone 8b 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 really do well. Starting your purple rock cress indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on March 15 in Zone 8b. In the coldest months of winter you can expect an average low temperature of 15°F.

Since the USDA zone info for Zone 8b is an average the actual date of last frost will vary from year to year. Since half of the time in Zone 8b last frost occurs after March 15 be ready to cover your purple rock cress if you have a surprise late frost.

USDA Zone Info for Zone 8b

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Zone 8b

You may be interested in your other planting guides for Zone 8b.