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

One way of estimating when it's possible to plant radicchio is to use the USDA zone info for Bourbonnais.

Planting Calendar for Radicchio

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

You can plant radicchio a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant radicchio in Bourbonnais 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. If you wait any later than that and your radicchio may not have a chance to grow to maturity. Starting your radicchio 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 Bourbonnais. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Bourbonnais is just an average the actual date of last frost is different every year. Since half of the time in Bourbonnais there is a last frost after April 15 be ready to cover your radicchio in the event of a late frost.

USDA Zone Info for Bourbonnais

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 Bourbonnais

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