The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. 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 monarda in Thief River Falls should be figured out by checking out the USDA zone info.

Planting Calendar for Monarda

Frost tolerance for monarda:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Monarda are barely cold tolerant which tells us that you can get them planted just a bit earlier than other frost tender plants.

The earliest that you can plant monarda in Thief River Falls is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant monarda and expect a good harvest is probably August. Any later than that and your monarda may not have a chance to grow to maturity. Starting your monarda indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Thief River Falls. In the coldest months of winter you can expect an average low temperature of -35°F.

Since the USDA zone info for Thief River Falls is just an average the actual date of last frost changes from year to year. Half of the time in Thief River Falls you get surprised by a frost after May 15 so be sure to be ready to cover your monarda if you have 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.