Radicchio varieties are named after several of the towns located in the Veneto region of northern Italy.
Direct-seed from May to July for your fall (cool season) harvest. The red color will deepen the longer you wait to harvest. Here in Ohio I try to time my harvests for Thanksgiving.
Here is a good trick to promote heading- in early fall cut all the leaves from above the crown of the plant. Remember, the cooler the weather, the better the taste!