One of the first steps you take when you are estimating 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.

The USDA zone info for Napa can be reviewed to estimate when to 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 little bit earlier in the year because they do well in moderate cold.

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

The last month that you can plant centaurea and expect a good harvest is probably October. Any later than that and your centaurea may not have a chance to really do well. Starting your centaurea indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Napa the average date of last frost happens on February 15. You can expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Napa is an average the actual date of last frost is different every year. Half of the time in Napa you get surprised by a frost after February 15 so be sure to be ready to protect your centaurea if you have a late frost.

USDA Zone Info for Napa

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°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 30°F.

Plants to Grow in Napa

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