The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. 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 radicchio in Naperville should be estimated by using the USDA zone info.

Planting Calendar for Radicchio

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

Since radicchio do well in moderate cold you can plant them a little bit earlier in the year than other frost tender plants.

The earliest that you can plant radicchio in Naperville 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 radicchio and expect a good harvest is probably September. Any later than that and your radicchio may not have a chance to fully mature. If you are starting your radicchio indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Naperville 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.

Just be sure to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Naperville and it will vary from year to year. Half of the time in Naperville it frosts late in the year after April 15 so make sure that you are ready to protect your radicchio in the event of one of those late frosts.

USDA Zone Info for Naperville

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 Naperville

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