Colorado Onions

“It’s hard to imagine civilization without onions.”
-Julia Child

Onions (Allium cepa) are versatile vegetables which add their special flavor characteristics to many popular recipes and may be prepared in a number of ways. They are separated into three color groups – yellow, red, and white.  Approximately 87% of the U.S. crop is devoted to yellow onion production, with about 8% red onions and 5% white onions.  Onions range in size from less than 1 inch in diameter (creamers/boilers) to more than 4.5 inches in diameter (super colossal).

Colorado Production

Colorado is one of the largest U.S. producers of onions by volume, and has an ideal climate for growing fall/winter storage onions. Our higher altitude and colder winter months keep insect and plant diseases at a minimum, thereby reducing pesticide use and ensuring high quality onions. Storage onions are generally harvested and shipped September through March. Specialty onions are available seasonally.

Selection, Handling, and Storage

Buying Onions

  • When purchasing onions, look for dry outer skins free of spots or blemishes. Onions should be heavy for their size and have no scent. Avoid onions that have begun to sprout.
  • Select green onions with firm white bottoms and crisp green tops that don’t show signs of wilt or decay.

Storing Onions

  • Store whole, unpeeled storage onions in a cool, dark, dry, well-ventilated place in a breathable bag–such as burlap or plastic mesh–to maintain air movement and improve storage life.
  • Green onions and whole sweet or mild onions with a high water content should be stored in the refrigerator to extend shelf life.
  • Peeled onions that are chopped, sliced, or whole can be stored in a sealed, dated, and labeled container in your refrigerator for up to 7 days. If not used within a week, freeze cut onions.

Why All the Tears? 

The process of cutting an onion allows contents within the onion cells to mix, producing a volatile sulfur compound that may react with your tears and form sulfuric acid. Refrigerating onions 30 minutes prior to cutting will slow down threaction and may help prevent tears.

Food Safety

For best quality and safety, always handle onions with care. Wash hands well before preparing; use a clean cutting board and cutting utensil; and refrigerate or discard cut onions within 2 hours.  

Although green onions are not grown on a large scale in Colorado, they are often available at local farmers’ markets. Commercially grown green onions require extensive handling during harvesting and packaging, creating multiple opportunities for contamination.  Be sure to store green onions in the refrigerator and thoroughly wash before preparing and consuming.

Classic Onion Soup


  • 4 large yellow onions, sliced 
  • 6 tablespoons butter
  • 1 tablespoon sugar
  • 2 quarts reduced-sodium chicken broth
  • 1/2 cup brandy (optional)
  • Salt and pepper, to taste
  • 1/2 baguette French bread, sliced, toasted
  • Grated Romano cheese

Melt butter in large saucepan. Add onions; cook over medium heat 12 minutes, or until tender and golden. Stir often. Add sugar and cook, stirring for 1 minute. Add broth; cover and bring to a boil. Reduce heat; simmer 12 minutes. If desired, add brandy; cook 2 minutes longer. Season with salt and pepper. To serve, ladle soup into bowl; float toast on soup. Sprinkle with cheese. 
Makes 6 servings.

Information and recipe courtesy of the National Onion Association:


Onions not only provide flavor, but they are also low in calories and offer layers of pungency or sweetness to a wide variety of foods. With only about 25 calories per 1/2-cup serving, onions are fat and cholesterol free, very low in sodium, high in vitamin C, and a good source of fiber and other key nutrients. 

They also provide health promoting phytochemicals. Onions are an outstanding source of polyphenols, including the flavonoid polyphenols. Within this flavonoid category, onions are an exceptional source of quercetin, which is anti-inflammatory and may help to protect against cancer. With all these benefits, onions are a healthy option for adding flavor to a savory recipe without adding many calories.


Onions preserve well and can be canned, dried, frozen, pickled, or made into a relish. Having a supply of dried or frozen onions on hand can not only save time but give a boost to many recipes and is a good way to store any extra onions until needed.

Freezing Onions

Drying Onions