One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Thief River Falls you can figure out when it's a good idea to plant copperleaf by checking out the USDA zone info.

Planting Calendar for Copperleaf

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

Copperleaf require warm weather which tells us that you must wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant copperleaf 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 copperleaf and expect a good harvest is probably August. If you wait any later than that and your copperleaf may not have a chance to fully mature. If you are starting your copperleaf indoors then you might be able to get away with starting them 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 may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Thief River Falls there is a last frost after May 15 so always be ready to cover your copperleaf 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.