The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to figure out when it's possible to plant centaurea by reviewing the USDA zone info for Sioux City.

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 just a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant centaurea in Sioux City is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant centaurea and expect a good harvest is probably September. Any later than that and your centaurea may not have a chance to fully mature. You can get started a little bit earlier by starting your centaurea indoors.

Last Frost Date

In Sioux City the average date of last frost happens on April 15. You can expect an average low temperature of -20°F in the coldest months of winter.

Since the USDA zone info for Sioux City is just an average the actual date of last frost changes from year to year. Since half of the time in Sioux City you get a frost after April 15 be ready to protect your centaurea if you have a late frost.

USDA Zone Info for Sioux City

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Sioux City

You may be interested in your other planting guides for Sioux City.