The USDA Zone info is a great tool for gardeners to help us determine 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.

You can determine when to plant asters in Oregon by referring to 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 do well in a little bit of cold which means that you can plant them a little earlier in the year than other plants that might not handle the cold.

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

Last Frost Date

In Oregon the average date of last frost happens on April 15. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Oregon may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Oregon there is a last frost after April 15 be ready to cover your asters in the event of one of those late frosts.

USDA Zone Info for Oregon

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Oregon

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