The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Washington you can estimate when it's possible to plant asters by looking at the USDA zone info.

Planting Calendar for Asters

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

Asters are one of those plants that can tolerate a little bit of cold weather which means that you can get them planted earlier than more sensitive plants.

The earliest that you can plant asters 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 asters and expect a good harvest is probably September. If you wait any later than that and your asters may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your asters indoors.

Last Frost Date

In Washington the average date of last frost happens on April 15. It might get as low as -10°F during the coldest months of winter.

Since the USDA zone info for Washington is an average the actual date of last frost is different every year. Half of the time in Washington you get surprised by a frost after April 15 so just be sure to be ready to cover your asters in the event of a late frost.

USDA Zone Info for Washington

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°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 -5°F.

Plants to Grow in Washington

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