One of the best tools that you have as gardeners to help us figure out 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 Great Falls can be read to determine when 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.

You can plant centaurea just a bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

The earliest that you can plant centaurea in Great 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. If you wait any later than that and your centaurea may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your centaurea indoors.

Last Frost Date

On average the last frost is on May 15 in Great Falls. You can expect an average low temperature of -30°F in the coldest months of winter.

Since the USDA zone info for Great Falls is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Great Falls there is a last frost after May 15 so be sure to be ready to protect your centaurea if you have a late frost.

USDA Zone Info for Great Falls

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Great Falls

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