In most areas, radicchio should be planted in late summer for a fall or early winter harvest before heavy frosts occur.

This is more labor-intensive but produces radicchio that, while naturally bitter, will have a crisp texture and a complex, bittersweet flavor. Most commercial growers use seeds designed to “self ...

For a continuous supply, sow a few seeds every four weeks ... including loose-leaf types and oak leaf lettuce, radicchio, rocket and endive.