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When to Plant Hardy Asters in Winthrop Harbor, IL

The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By checking out the USDA zone info for Winthrop Harbor it's possible to estimate when it's a good idea 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 means that you can get them planted just a bit earlier than more sensitive plants.

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 Winthrop Harbor 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. Starting your hardy asters indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Just be sure to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Winthrop Harbor and it will vary from year to year. Since half of the time in Winthrop Harbor there is a last frost after April 15 be ready to protect your hardy asters if you have a surprise late frost.

USDA Zone Info for Winthrop Harbor

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 Winthrop Harbor

You may be interested in your other planting guides for Winthrop Harbor.