Unheated greenhouses may be used all year in areas where the temperatures never dip below the freezing point, as Green House Secrets mentions. In other areas, they can be used to extend the growing season of plants like vegetables, small fruits, annuals and perennials.
About this Author
Marie Notnats enjoys learning about new topics and teaching people new skills. She has been writing professionally since 2008. She is a professional horticulturist with a Bachelor of Science degree in horticulture from Brigham Young University. She writes for About.com, Examiner.com, eHow, and assorted gardening blogs.