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.

You can estimate when it's possible to plant pentas in Thief River Falls by using the USDA zone info.

Planting Calendar for Pentas

Frost tolerance for pentas:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Pentas are not cold tolerant which tells us that you have to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant pentas 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 pentas and expect a good harvest is probably August. You probably don't want to wait any later than that or else your pentas may not have a chance to really do well. You can get started a little bit earlier by starting your pentas indoors.

Last Frost Date

In Thief River Falls the average date of last frost happens on May 15. It might get as low as -35°F during the coldest months of winter.

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 there is a last frost after May 15 so be sure to be ready to cover your pentas 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.