How should onions be stored and wrapped?

Onions and other root vegetables (which grow in the soil) maintain their best quality for longest when stored at 55ºF, the temperature of the soil. Onions need to be in “breathable” wrapping to avoid humidity, sprouting, mold growth, or the growth of   toxic spores.  Also, if onions are stored at too warm a temperature or in the presence of sunlight, they will begin to sprout, and the onion will become mushy and/or rot.  

In the pantry, basement, closet, or garage:  You can store onions in the leg of a pair of pantyhose, tying a knot between each one.  When you need an onion, cut it off above the knot. Alternatively, they can be put in a mesh bag, wire basket, or crate. They should be stored at 32°-55°F in an area of low humidity (the relative humidity not exceeding 56-70%).  Stored this way, onions may keep for several months. Before refrigeration was available, potatoes and onions were stored in root cellars (about 55°F) , where they kept well over the winter.  Yellow onions store better  than white ones, and the white ones last longer than the purple or brown.

In the refrigerator: If you have no cool space (32°F - 55°F) outside the fridge, the next best spot for onions is in the fridge.  If stored in the refrigerator, whole onions should be wrapped loosely in paper or in a plastic bag  that has holes punctured in it (for ventilation).  Loose wrapping will prevent dangerous spores from germinating.  Chopped or sliced onions should be refrigerated (or frozen) and stored for a maximum of 7 days. 

Onions and other fruits and vegetables, can  also be kept in produce savers, which come in different sizes. Rubbermaid® produce savers let some air in for fruits and vegetables to “breathe”  and  have a  “crisp tray” that holds the product above moisture that may collect at the bottom of the container. Perhaps other brands have similar features.   

In the freezer: Onions can be frozen whole or cut up. To freeze whole onions, first peel, wash, and core.  Then place them in a freezer container or freezer wrap.  Keep in mind that freezing any raw whole vegetable is likely to result in a poor quality product. Because of the time it takes the center to freeze, large ice crystals are likely to form inside the center, allowing cellular material to leak out.  Freeze chopped onions by first placing them on a cookie sheet.  After they’re frozen, put them in a freezer bag or container.

Source(s):

What’s Cooking  America?  “”Regular Onions and Sweet Onions”
http://whatscookingamerica.net/onion.htm

Harvesting and Storing Onions. Richard Jauron,Extension Horticulturalist Iowa State University. 7/27/2009.  http://www.extension.iastate.edu/news/2009/jul/062201.htm

Growing Vegetables - Leeks & Spring Onions.  Elyse Grau - 3/17/2009 
http://en.allexperts.com/q/Growing-Vegetables-740/2009/3/Leeks-Spring-Onions.htm

University of Arkansas Home Gardening Series.  “About Onions: Frequently Asked Questions”
http://www.uaex.edu/Other_Areas/publications/PDF/FSA-6014.pdf

Rubbermaid.com  “Produce Saver”

Susan Brewer, Ph.D., University of Illinois, Department of Food Science and Human Nutrition

Link(s):

Harvesting and Storing Onions. Richard Jauron,Extension Horticulturalist Iowa State University. 7/27/2009.  http://www.extension.iastate.edu/news/2009/jul/062201.htm