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

In Mount Rainier you can estimate when to plant purple rock cress by looking at the USDA zone info.

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.

Since purple rock cress are one of those plants that can tolerate quite a bit of cold weather you can plant them earlier in the year than other frost tender plants.

The earliest that you can plant purple rock cress in Mount Rainier 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 fully mature. Starting your purple rock cress indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Mount Rainier the average date of last frost happens on April 15. It might get as low as 0°F during the coldest months of winter.

Always keep in mind that USDA zone info for Mount Rainier is an average and the actual date of last frost will vary from year to year. Half of the time in Mount Rainier there is a last frost after April 15 so be sure to be ready to cover your purple rock cress if you have a surprise late frost.

USDA Zone Info for Mount Rainier

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 Mount Rainier

You may be interested in your other planting guides for Mount Rainier.