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

You can determine when you can plant asters in Walla Walla 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 are one of those plants that can tolerate a little bit of cold weather you can plant them a little bit earlier in the year than more sensitive plants.

The earliest that you can plant asters in Walla Walla 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. You can get started a few weeks earlier by starting your asters indoors.

Last Frost Date

The average date of last frost is April 15 in Walla Walla. You can expect an average low temperature of 0°F in the coldest months of winter.

Keep in mind that USDA zone info for Walla Walla is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Walla Walla last frost occurs after April 15 so always be ready to cover your asters in the event of a late frost.

USDA Zone Info for Walla Walla

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 Walla Walla

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