Cold weather, including frost, can cause onion plants to bolt, meaning to produce a tall stem and flower. Onion plants that bolt have smaller bulbs and do not store well.
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Sandy Mitchell is an Ohio-based writer, blogger and editor. Among other projects, she writes for About.com and "The Better Drink." Before devoting herself full time to writing, Mitchell was a travel agent and cruise school instructor for 18 years. She holds a Bachelors of Science in business administration from Bowling Green State University.