One of the best tools that you have as gardeners to help us estimate 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.

A way of making a decision about when you can plant asters is to consult the USDA zone info for Winnetka.

Planting Calendar for Asters

Frost tolerance for asters:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Asters are moderately cold tolerant which tells us that you can plant them earlier than more sensitive plants.

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

The last month that you can plant asters and expect a good harvest is probably September. Any later than that and your asters may not have a chance to fully mature. You can get started a little bit earlier by starting your asters indoors.

Last Frost Date

The average date of last frost is April 15 in Winnetka. You can expect an average low temperature of -15°F in the coldest months of winter.

Remember that USDA zone info for Winnetka may not be accurate from year to year and the actual date of last frost changes from year to year. Half of the time in Winnetka you get surprised by a frost after April 15 so make sure that you are ready to protect your asters if you have one of those late frosts.

USDA Zone Info for Winnetka

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 Winnetka

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