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.

By reviewing the USDA zone info for Ottumwa you will be able to determine when you can 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 a bit earlier in the year because they do well in moderate cold.

The earliest that you can plant centaurea in Ottumwa 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 few weeks earlier by starting your centaurea indoors.

Last Frost Date

On average the last frost is on April 15 in Ottumwa. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Ottumwa is not always accurate the actual date of last frost changes from year to year. Half of the time in Ottumwa you get surprised by a frost after April 15 so be sure to be ready to protect your centaurea in the event of a surprise late frost.

USDA Zone Info for Ottumwa

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Ottumwa

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