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.

The USDA zone info for Ironwood should be read 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.

Since centaurea are moderately cold tolerant you can plant them a little bit earlier in the year than other frost tender plants.

The earliest that you can plant centaurea in Ironwood 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. Starting your centaurea indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Ironwood. In the coldest months of winter you can expect an average low temperature of -30°F.

Always keep in mind that USDA zone info for Ironwood is just an average and the actual date of last frost changes from year to year. Half of the time in Ironwood it frosts late in the year after May 15 so just be sure to be ready to cover your centaurea in the event of a surprise late frost.

USDA Zone Info for Ironwood

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 Ironwood

You may be interested in your other planting guides for Ironwood.