When to Plant Hardy Asters in Harrisburg, IL

One of the first steps you take when you are determining 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.

You can determine when to plant hardy asters in Harrisburg by using 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 just a tiny bit earlier in the year because they are barely cold tolerant.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant hardy asters
Possibly ok, but a risky time to plant hardy asters
Probably not a good time to plant hardy asters

The earliest that you can plant hardy asters in Harrisburg 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. You probably don't want to wait any later than that or else your hardy asters may not have a chance to really do well. If you are starting your hardy asters indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Harrisburg. In the coldest months of winter you should expect an average low temperature of -5°F.

It's important to remember that USDA zone info for Harrisburg may not be accurate from year to year and the actual date of last frost changes from year to year. Since half of the time in Harrisburg last frost occurs after April 15 be ready to protect your hardy asters in the event of one of those late frosts.

USDA Zone Info for Harrisburg

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-5°F
Highest Expected Low0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Harrisburg

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