Year round production of greenhouse grown french tarragon

Abstract:

Potted tarragon plants were grown in a greenhouse under short days (8hr) or long days (16 hr), combined with a pretreatment 
of gibberellic acid (GA3) spray, or several weeks of 4°C cold. Long days promoted shoot growth whereas plants grown under short days grew in basal rosette form most of the time. Cold pretreatment was not necessary to break dormacy; however, it did significantly increase total production. GA3 pretreatment was not as successful as cold in promoting regrowth. Regular harvest of the foliage stimulated growth under long days.