The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to estimate when you can plant purple rock cress by looking at the USDA zone info for Washington.

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.

You can plant purple rock cress much earlier in the year because they are very cold tolerant.

The earliest that you can plant purple rock cress in Washington 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. Starting your purple 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 March 15 in Washington. In the coldest months of winter you should expect an average low temperature of 10°F.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Washington and it changes from year to year. Half of the time in Washington it frosts late in the year after March 15 so be sure to be ready to protect your purple rock cress in the event of a surprise late frost.

USDA Zone Info for Washington

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Washington

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