The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of estimating when to plant centaurea is to look at the USDA zone info for Worthington.

Planting Calendar for Centaurea

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

Centaurea do well in mild cold which tells us that you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant centaurea in Worthington 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 grow to maturity. If you are starting your centaurea indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Worthington the average date of last frost happens on May 15. It might get as low as -25°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Worthington and it changes from year to year. Half of the time in Worthington you get surprised by a frost after May 15 so make sure that you are ready to cover your centaurea in the event of a surprise late frost.

USDA Zone Info for Worthington

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Worthington

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