Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By checking out the USDA zone info for Thief River Falls you should be able to figure out when it's a good idea to plant mimulus.

Planting Calendar for Mimulus

Frost tolerance for mimulus:	Not tolerant of frost.
When to plant:	After the last frost.

Since mimulus do not do well in cold weather you must wait until after the last frost when the weather gets warmer before you can plant them.

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

The last month that you can plant mimulus and expect a good harvest is probably August. You probably don't want to wait any later than that or else your mimulus may not have a chance to grow to maturity. Starting your mimulus indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on May 15 in Thief River Falls. It might get as low as -35°F during the coldest months of winter.

Keep in mind 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 can change quite a bit from year to year. Half of the time in Thief River Falls it frosts late in the year after May 15 so be sure to be ready to cover your mimulus if you have 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.