Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Thief River Falls should be used to estimate when to plant campanula.

Planting Calendar for Campanula

Frost tolerance for campanula:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Campanula are one of those plants that can tolerate a little bit of cold weather which tells us that you can start planting them earlier than plants that are more sensitive to the cold.

The earliest that you can plant campanula 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 campanula and expect a good harvest is probably August. Any later than that and your campanula may not have a chance to really do well. Starting your campanula indoors is a great way to get them started a little bit earlier.

Last Frost Date

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

Just be sure to remember that USDA zone info for Thief River Falls is just an average and the actual date of last frost changes from year to year. Half of the time in Thief River Falls it frosts late in the year after May 15 so just be sure to be ready to cover your campanula in the event of a surprise 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.