Forcing Chicory - Do not plant seeds too early for forcing roots. The roots may grow too large or develop flower stalks, making them unsuitable for forcing. Store the roots in a cool place with high moisture such as an outdoor vegetable pit or underground cellar. During the winter and early spring, roots can be prepared in a new forcing box every two to three weeks for a continuous supply. Most gardeners put their forcing boxes in the basement because lack of light does not affect the quality of the Witloof heads.
Some gardeners use cold frames or hotbeds or force in a trench in the garden.
A sheet of clear or black polyethylene film should be placed over the trench to increase soil temperature. Fill with sand or fine soil sifted in between the roots up to the tops of the crowns. Add 6 to 8 inches of sand or sawdust over the crowns. The blanched tops will grow into compact, pointed heads. The proper temperature for forcing is between 60 and 70 degrees F. Water thoroughly after preparing the forcing box.