One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant hardy asters in Joliet can be estimated 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.

Hardy Asters are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can start planting them slightly earlier than more sensitive plants.

The earliest that you can plant hardy asters in Joliet 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. If you are starting your hardy asters indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Just be sure to remember that USDA zone info for Joliet is an average and the actual date of last frost will vary from year to year. Half of the time in Joliet you get a frost after April 15 so make sure that you are prepared to cover your hardy asters if you have a late frost.

USDA Zone Info for Joliet

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 Joliet

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