Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Superior should be looked at to estimate when it's a good idea to plant radicchio.

Planting Calendar for Radicchio

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

Radicchio do well in moderate cold which tells us that you can get them planted earlier than other plants that might not handle the cold.

The earliest that you can plant radicchio in Superior 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 radicchio and expect a good harvest is probably August. If you wait any later than that and your radicchio may not have a chance to really do well. You can get started a little bit earlier by starting your radicchio indoors.

Last Frost Date

On average all chance of frost has passed is on May 15 in Superior. It might get as low as -25°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Superior and it changes from year to year. Since half of the time in Superior there is a last frost after May 15 be ready to cover your radicchio in the event of a late frost.

USDA Zone Info for Superior

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Superior

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