One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant rock cress in Thief River Falls can be determined by using the USDA zone info.

Planting Calendar for Rock Cress

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

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

The earliest that you can plant rock cress in Thief River Falls 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. If you wait any later than that and your rock cress may not have a chance to grow to maturity. If you are starting your rock cress indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Thief River Falls the average date of last frost happens on May 15. You should expect an average low temperature of -35°F in the coldest months of winter.

Since the USDA zone info for Thief River Falls is not always accurate the actual date of last frost will vary from year to year. Half of the time in Thief River Falls it frosts late in the year after May 15 so make sure that you are ready to cover your rock cress in the event of a late frost.

USDA Zone Info for Thief River Falls

Here is the info for USDA Zone 3b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-35°F
Highest Expected Low	-30°F

This means that on a really cold year, the coldest it will get is -35°F. On most years you should be prepared to experience lows near -30°F.

Plants to Grow in Thief River Falls

You may be interested in your other planting guides for Thief River Falls.