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.

The USDA zone info for Lake Oswego should be used to figure out when to plant asters.

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 moderately cold tolerant you can plant them just a bit earlier in the year than other frost tender plants.

The earliest that you can plant asters in Lake Oswego 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. Any later than that and your asters may not have a chance to grow to maturity. If you are starting your asters indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on March 15 in Lake Oswego. You can expect an average low temperature of 15°F in the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Lake Oswego and it is different every year. Since half of the time in Lake Oswego you get a frost after March 15 be ready to cover your asters if you have a surprise late frost.

USDA Zone Info for Lake Oswego

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Lake Oswego

You may be interested in your other planting guides for Lake Oswego.