The flower grows in water:

After that delicate phase the radicchio roots are positioned in special tubs where resurgence water flows and then covered, so that, the light cannot pass through.
The lukewarm water, about 12/15°, speeds up the plants of radicchio to the resumption of life and after 10/20 days this cycle is completed. 
The typical red colour's development of the plant takes place thanks to the utilisation of the only supplies inside the root.
When the tufts arrived at the right level of maturing and development, the plants are taken from the basins and placed in mild places, at steady temperature, with the roots leaned on straw and sand.
Before the radicchio is put on the market, this is carefully cleaned.

Knowing and Choosing the authentic “Radicchio Rosso di Treviso”:

The radicchio rosso trevigiano has got the “IGP” (Protected Geographic Indication) mark for al lot of its own peculiarities: the name, the production area and the manufacturing process; that’s the reason why these plants are controlled all over Europe. The body of Community legislation has recognized officially that product and therefore the radicchio is appreciated for the weight of history and for the human skill. 
That is not only a commercial mark, but also a true guarantee from the producer to the consumer .
The radicchio rosso di Treviso can also boast of a good manufacturing process and, above all, the regrowth in resurgence water, that happens in a vegetative cycle end: in that way the plant can grow in a vigorous way .