What is Vernalization?
Some plants will not flower until after they have been exposed to cold temperatures. This exposure to cold temperatures, resulting in physiological changes in the plant, is called vernalization. Not all plants have a vernalization requirement, and the degree of vernalization required can vary within a species. What are “vernalization days”? Vernalization days (VD) are a measure of cold temperature, similar to growing degree days (GDD) as a measure of warm temperatures. Contrary to popular belief, the best vernalization temperatures are in the 40 F – 50 F range, not at colder temperatures. Vernalization is a biological process and plants have to be biologically active – not frozen – for it to occur. Does wheat have a vernalization requirement? Winter wheat does have a vernalization requirement. Most spring wheats do not, or have very low vernalization requirements. Do all winter wheats have the same vernalization requirement? No. The table below groups varieties with low, intermediate,
Vernalization is a stage in the development of many plants, most notably bulbs, fruit trees, and nut trees. This stage involves exposure to cold temperatures for a set period of time, followed by a period of increased photosensitivity which allows the plant to start producing flowers. There are a number of reasons why vernalization is important to plants, and it is also useful to be aware of when forcing plants to bloom indoors or to bloom earlier than they usually do. From the point of view of plants, vernalization is an important trait. It alerts the plants to the fact that winter has passed, indicating that it is safe to start producing buds and flowers for the spring. In plants which depend on vernalization as part of their life cycle, the purpose of this stage of development is to encourage flowering at the right time, while also protecting the plant from blooming at the wrong time. Some plants experience what is known as obligate vernalization, which means that the plant must be
Vernalization is the acquisition of the competence to flower in the spring by exposure to the prolonged cold of winter. The word vernalization comes from the Latin word “vernus,’ meaning “of the spring.” Many temperate plants have a vernalization requirement and must experience a period of low winter temperature to initiate or accelerate the flowering process, or, as the case with many fruit tree species, to actually break dormancy, prior to flowering.
