One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can determine when it's the best time to plant centaurea in Washington 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.

Since centaurea are one of those plants that can tolerate a little bit of cold weather you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant centaurea in Washington 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. If you wait 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 all chance of frost has passed is on April 15 in Washington. In the coldest months of winter you can expect an average low temperature of -15°F.

Just be sure to remember that USDA zone info for Washington is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Washington you get surprised by a frost after April 15 so just be sure to be ready to protect your centaurea in the event of a surprise late frost.

USDA Zone Info for Washington

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 Washington

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