In order to produce nice white endives the plant is traditionally cultivated under iron plates, in complete darkness. In the winter the soil is heated by a watersystem under the ground and the heat is produced by little coal fires, which have to be filled up every so many hours.
When I was a young boy hundreds of farmer families in our area lived upon this unique but hard labour business. Due to modern hydro-cultivation techniques and big competition from abroad only a handfull farmers remain in our village.