One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Lake Oswego you can determine when it's the best time to plant hardy asters by referring to the USDA zone info.

Planting Calendar for Hardy Asters

Frost tolerance for hardy asters:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant hardy asters a bit earlier in the year because they are one of those plants that can tolerate a tiny bit of cold weather.

The earliest that you can plant hardy asters in Lake Oswego is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant hardy asters and expect a good harvest is probably August. Any later than that and your hardy asters may not have a chance to grow to maturity. Starting your hardy asters indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is March 15 in Lake Oswego. In the coldest months of winter you can expect an average low temperature of 15°F.

Since the USDA zone info for Lake Oswego is just an average the actual date of last frost is different every year. Half of the time in Lake Oswego it frosts late in the year after March 15 so make sure that you are ready to cover your hardy asters if you have one of those late frosts.

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.