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.

A common way of determining when it's a good idea to plant centaurea is to use the USDA zone info for Humboldt.

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 start planting them earlier than more sensitive plants.

The earliest that you can plant centaurea in Humboldt 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 couple of weeks earlier.

Last Frost Date

In Humboldt the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of 0°F.

Keep in mind that USDA zone info for Humboldt is just an average and the actual date of last frost will vary from year to year. Since half of the time in Humboldt you get a frost after April 15 be ready to protect your centaurea if you have a late frost.

USDA Zone Info for Humboldt

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Humboldt

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