One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of determining when it's possible to plant chrysocephalum is to use the USDA zone info for Thief River Falls.

Planting Calendar for Chrysocephalum

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

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

The earliest that you can plant chrysocephalum 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 chrysocephalum and expect a good harvest is probably August. You probably don't want to wait any later than that or else your chrysocephalum may not have a chance to grow to maturity. If you are starting your chrysocephalum indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Remember that USDA zone info for Thief River Falls is just an average and the actual date of last frost changes from year to year. Half of the time in Thief River Falls it frosts late in the year after May 15 so make sure that you are prepared to cover your chrysocephalum in the event of 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.