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.

A way of estimating when you can plant centaurea is to look at the USDA zone info for Riverdale.

Planting Calendar for Centaurea

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

Since centaurea do well in moderate cold you can plant them a little bit earlier in the year than plants that are more sensitive to the cold.

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

Last Frost Date

On average the last frost is on March 15 in Riverdale. In the coldest months of winter you should expect an average low temperature of 10°F.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Riverdale and it will vary from year to year. Half of the time in Riverdale last frost occurs after March 15 so be sure to be ready to protect your centaurea in the event of one of those late frosts.

USDA Zone Info for Riverdale

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

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

Plants to Grow in Riverdale

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