Look for:
radicchio heads that are compact, with leaves that are fresh, moist, and tender.
Avoid:
radicchio with leaves that are torn, dried, limp, or yellowed.
Seasonality: All year
Storing Radicchio
Store radicchio unwashed in the coldest section of the refrigerator for no more 3 days. Do not wrap or cover.
Preparing Radicchio
Rinse in cold water. Trim off the bottom stem as you would lettuce and cut out the core in a cone. If the radicchio has a root, trim it off, but do not discard. Use it as you would a radish or other root vegetable. If the leaves look wilted, soak them in a bowl of cold water to revive.