Onion sprouts are immature onion plants that have grown for a period of only 10 to 15 days. The sprouts are eaten in this juvenile form, usually when they are from 2 to 3 inches (about 5 to 8 centimeters) in height. They provide a very mild taste when compared to a fully formed onion. In contrast to other seeds, onion sprouts grow the actual plant from their seeds instead of the root system. Onion sprouts can be grown at home and, if cultivated without pesticides and herbicides, would then be valued for their nutritional properties and their lack of chemicals often found in commercial growing crops.
As a member of the allium family, onion sprouts are the same variety of plant that includes garlic. Although individual plants might vary, the sprouts have a smell and taste similar to onions, although they are not as intense. The way they grow makes them similar in appearance to a small scallion.
Onion sprouts can be grown in a very small space in the home. They require indirect sunlight once they have started to show green shoots, but otherwise are easy to germinate and grow. This method of acquiring sprouts is popular because the amount of chemicals that are used can be strictly controlled or eliminated completely. Commercial home sprouting systems exist that can automate nearly every step of the process, allowing the sprouts to be grown any time of year. They can even be successfully grown with hydroponic or aeroponic methods.
In East Asian countries, different types of sprouts have been used in cooking for a long time. They can be fried with other ingredients to provide a subtle flavor or used raw as a garnish or textural complement. People who follow a raw food diet have found sprouts to be an integral part of their nutritional intake. Sprouts also can be substituted for certain greens and added to salads.
There are several nutritional benefits to consuming onion sprouts. They are high in protein and also are a good source of vitamins A, B and C. They also have significant amounts of potassium, iron and calcium. When compared to a mature onion, the sprouts have a much higher concentration of vitamins overall.
A factor to be concerned about when sprouting seeds is that their growing conditions can encourage the growth of bacteria. This can lead to the development of E. coli and salmonella in the plants. The bacteria can be destroyed, however, with proper washing or by cooking the sprouts.