One of the first steps you take when you are getting a good idea your gardening schedule is find your 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.

The first opportunity to plant calendula in Thief River Falls can be determined by referring to the USDA zone info.

Planting Calendar for Calendula

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

Calendula are moderately cold tolerant which tells us that you can plant them earlier than other plants that might not handle the cold.

The earliest that you can plant calendula 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 calendula and expect a good harvest is probably August. If you wait any later than that and your calendula may not have a chance to really do well. Starting your calendula 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. You can expect an average low temperature of -35°F in the coldest months of winter.

Remember that USDA zone info for Thief River Falls is not always accurate and the actual date of last frost is different every year. Half of the time in Thief River Falls last frost occurs after May 15 so just be sure to be ready to cover your calendula in the event of one of those late frosts.

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.