One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for International Falls can be reffered to in order to figure out when it's the best time to plant centaurea.

Planting Calendar for Centaurea

Frost tolerance for centaurea:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Centaurea tend to make it in some cold which means that you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant centaurea in International 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 centaurea and expect a good harvest is probably August. Any later than that and your centaurea may not have a chance to really do well. Starting your centaurea indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in International Falls. In the coldest months of winter you should expect an average low temperature of -40°F.

Since the USDA zone info for International Falls is just an average the actual date of last frost changes from year to year. Half of the time in International Falls it frosts late in the year after May 15 so make sure that you are ready to protect your centaurea in the event of one of those late frosts.

USDA Zone Info for International Falls

Here is the info for USDA Zone 3a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-40°F
Highest Expected Low	-35°F

This means that on a really cold year, the coldest it will get is -40°F. On most years you should be prepared to experience lows near -35°F.

Plants to Grow in International Falls

You may be interested in your other planting guides for International Falls.