One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Rock Springs you can figure out when it's the best time to plant centaurea by checking out the USDA zone info.

Planting Calendar for Centaurea

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

Centaurea are moderately cold tolerant which means that you can get them planted earlier than more sensitive plants.

The earliest that you can plant centaurea in Rock Springs 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. You can get started a few weeks earlier by starting your centaurea indoors.

Last Frost Date

The average date of last frost is April 15 in Rock Springs. You can expect an average low temperature of -20°F in the coldest months of winter.

Keep in mind that USDA zone info for Rock Springs is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Rock Springs there is a last frost after April 15 be ready to protect your centaurea in the event of a late frost.

USDA Zone Info for Rock Springs

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 Rock Springs

You may be interested in your other planting guides for Rock Springs.