The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant spearmint in Thief River Falls should be estimated by reviewing the USDA zone info.

Planting Calendar for Spearmint

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

You can plant spearmint earlier in the year because they do well in cold.

The earliest that you can plant spearmint 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 spearmint and expect a good harvest is probably August. Any later than that and your spearmint may not have a chance to really do well. If you are starting your spearmint indoors then you might be able to get away with starting them a few weeks 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 the actual date of last frost is not always accurate because it is based on the USDA zone info for Thief River Falls and it will vary from year to year. Half of the time in Thief River Falls you get surprised by a frost after May 15 so always be ready to protect your spearmint if you have 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.