Fluctuating temperatures cause the onion to enter and leave periods of dormancy and growth. The onion believes that it has completed its biennial cycle of going from seed to seed and it finalizes the cycle by sending up a flower, according to the Texas A&M Agri-Life Extension service.
About this Author
Lee Roberts has written professionally in different capacities throughout her career. She has written for not-for-profit and commercial entities since she received her B.A in sociology from the University of Michigan in 1986. She has been published on eHow.com. She is currently writing an extensive work of fiction.