One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to figure out when it's possible to plant rock cress by looking at the USDA zone info for Ketchikan.

Planting Calendar for Rock Cress

Frost tolerance for rock cress:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since 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 more sensitive plants.

The earliest that you can plant rock cress in Ketchikan 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 rock cress and expect a good harvest is probably September. You probably don't want to wait any later than that or else your rock cress may not have a chance to really do well. Starting your rock cress indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Ketchikan. In the coldest months of winter you can expect an average low temperature of 5°F.

Since the USDA zone info for Ketchikan is an average the actual date of last frost will vary from year to year. Half of the time in Ketchikan last frost occurs after April 15 so make sure that you are prepared to protect your rock cress if you have a surprise late frost.

USDA Zone Info for Ketchikan

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 Ketchikan

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