The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of estimating when it's a good idea to plant rock cress is to check out the USDA zone info for Palmer.

Planting Calendar for Rock Cress

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

Rock Cress can survive in quite a bit of cold which tells us that you can plant them quite a bit earlier in the year than more sensitive plants.

The earliest that you can plant rock cress in Palmer is March. However, you really should wait until April 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 August. You probably don't want to wait any later than that or else your rock cress may not have a chance to fully mature. You can get started a few weeks earlier by starting your rock cress indoors.

Last Frost Date

On average the last frost has passed is on May 15 in Palmer. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Palmer is an average the actual date of last frost changes from year to year. Half of the time in Palmer last frost occurs after May 15 so make sure that you are prepared to cover your rock cress if you have one of those late frosts.

USDA Zone Info for Palmer

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Palmer

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