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.

In Silverton you can figure out when it's the best time 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 do well in cold you can plant them much earlier in the year than other plants that might not handle the cold.

The earliest that you can plant purple rock cress in Silverton 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. You probably don't want to wait any later than that or else your purple rock cress may not have a chance to fully mature. 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 March 15 in Silverton. In the coldest months of winter you can expect an average low temperature of 10°F.

Keep in mind that USDA zone info for Silverton may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in Silverton you get a frost after March 15 so just be sure to be ready to protect your purple rock cress in the event of a surprise late frost.

USDA Zone Info for Silverton

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 Silverton

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