Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The earliest that you can plant asters in Washington can be estimated by reviewing 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.

Since asters do well in moderate cold you can plant them a little earlier in the year than other frost tender 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. You probably don't want to wait any later than that or else your asters may not have a chance to really do well. Starting your asters indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is 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 the actual date of last frost is an average because it is based on the USDA zone info for Washington and it will vary from year to year. Since half of the time in Washington there is a last frost after April 15 be ready to protect your asters if you have 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.