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.

By checking out the USDA zone info for South Portland you should be able to figure out when to plant hardy asters.

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.

Hardy Asters do ok in moderate cold which tells us that you can plant them slightly earlier than plants that are more sensitive to the cold.

The earliest that you can plant hardy asters in South Portland 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. If you wait any later than that and your hardy asters may not have a chance to fully mature. If you are starting your hardy asters indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In South Portland the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -15°F.

It's important to remember that USDA zone info for South Portland is just an average and the actual date of last frost changes from year to year. Half of the time in South Portland it frosts late in the year after April 15 so be sure to be ready to protect your hardy asters if you have a late frost.

USDA Zone Info for South Portland

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 South Portland

You may be interested in your other planting guides for South Portland.