Find a sunny, moist, but well-drained location for planting. A site with rocks nearby provides the heat that Italian dandelions love.
Prepare the soil by adding organic matter, such as compost. Turn it with a shovel, then break the clods and rake until finely textured. Don't worry amending it with fertilizer; Italian dandelions are wildflowers and thrive in weak soils.
Sow the seeds from March to May, whenever the danger of frost is past, if you want plants to blossom in mid- to late summer. Chicory-type Italian dandelion matures in about five weeks; it can take as many as 12 weeks for the radicchio variety. Plant chicory seeds 1/8 inch deep and radicchio 1/4 to 1/2 inch deep; place a few seeds in each hole and space the holes 12 inches apart.
Water the seedbed twice daily if you live in a semi-arid region. If your climate has more rainfall, water every other day on dry days. Use a fine spray to avoid causing the seeds to move. Continue on this schedule until the seedlings are about 2 inches high, then gradually reduce watering. Don't let the plants wilt, because stress limits growth.
When the seedlings are about 5 inches tall and sturdy enough to handle, thin them to maintain a distance of 12 inches between plants.