Cultivation of the turnip plant, Brassica campestris, in glass house conditions under 24 hour illumination with a 360Watt sodium light (above). The turnip, a biennial plant, normally needs to overwinter in the ground in order to flower. Under glass house conditions of continuous light & constant temperatures they flower in three weeks. It is achieved by a process of selection over many generations of the quickest flowering lines. These plants have been treated with a mutagenizing agent in order to select new genetic types for breeding. Each plant is numbered & labelled. Plastic bubble film (right wall) can be seen in use as thermal insulation.