The many varieties of radicchio cultivable in the garden all belong to the genus chycorium, as well as scarola, endive and other salads. There are numerous varieties of Cychorium, the most famous being surely the radicchio of Treviso, elongated, with very pronounced ribs and dark red leaves, the radicchio of Castelfranco, with yellow-white leaves and red streaks, the radicchio of Chioggia and Verona , which forms rounded tufts with red leaves.
It is a salad with tufted growth, with generally reddish, rosy or yellow leaves and a particular bitter taste; in reality, if cultivated directly in the open like a common salad, we will obtain tufts of predominantly green color, with red or pink streaks.
Chicories are perennial vegetables, although they need a light shelter from the most intense frosts; it is a late salad, which is sown starting from the summer, to obtain an autumn and winter harvest. It is sown directly at home, taking care to thin out the small plants so as to obtain rows at least 35 cm apart from each other, to allow the head to develop at its best; generally the plants begin to produce the characteristic ball when the autumn climate becomes cool; plus the climate is fresh and the Cychorium is more tasty. Watering is provided to seeds and young seedlings, as the summer climate is generally warm and dry. With the arrival of autumn we can thin out or even suspend watering, given that the climate in this season tends to be already humid. We avoid watering excessively, and we only supply water if the soil is well dry. Starting from September-October we can begin to take the heart of the tufts; leaving the root untouched, the plant will produce more clumps, and a slight protection from the winter cold will guarantee fresh Cychorium for the whole winter until spring.
Cultivating the plants as a common salad, we will obtain not too compact tufts, with green variegated red leaves, slightly bitter, and quite fleshy leaves.
In order to get completely red heads of cychorium we will have to make sure that the plants receive little light; if we let the head develop a lot it will tend to close on itself, so the heart inside the leaves will not receive light: the diminished production of chlorophyll will make the small heart inside the tufts of bright red color.
If we want to obtain completely red tufts, even in the outer leaves, as soon as the head is well formed we can cover it with an overturned vase, so as to avoid receiving direct sunlight; in this way the whole head, even the external leaves, will become dark red.
Radicchio - Cychorium: Production of radicchio
In the Veneto areas, where radicchio is a culture, almost a religion, not simply a cultivation, bleaching is an art; in the large fields of radicchio of Treviso, Castelfranco, Chioggia, Verona, this operation begins as soon as the tufts have reached a good size. Keeping the roots, the tufts are gathered in large bunches leaning against each other, placed in the field in a fairly dark place, protected from light. In the next phase the decks are cleaned from the ruined leaves and placed in tanks, in the dark and with running water. After 10-12 days from the tanks the radicchio is further cleaned of any residues or damaged leaves and is placed in cool, very humid and completely dark rooms. Through these steps, which last a few weeks, the radicchio gains in flavor and crunchiness and turgidity of the foliage; at the end of the bleaching most of the root and all withered or ruined leaves are raised, obtaining only the heart of the head, with the characteristic crisp and thick leaves. For the amateur vegetable grower the bleaching of radicchio is certainly an excessively complicated operation; this method of cultivation is generally followed only by those who intend to sell the product of their land, being very long and expensive.