Life is Better with Onions

Bunching onions can be easily grown and used in cooking or salads

Life is Better with Onions

Master Gardener Scoop – February 21, 2018

Linda Summers,
Master Gardener

This time of the year when air temperatures begin to warm slightly and days lengthen, people consider planting their cool season crops.
Cool weather crops, especially those of the onion and cabbage families, are hardy or cold resistant. They may be planted as soon as the soil can be worked in the spring.
This might be as much as six weeks before the last frost date. Onions (Allium cepa) are cool-season vegetables that can be planted in March or early April and grow quite successfully in Illinois.
Onions are in the family of alliums, which includes chives, shallots, leeks, and garlic as well as many flowering ornamental species.
There are three methods of growing onions: from sets, transplants, or seed. Growing onions from sets or from transplants is preferable to growing them from seed, which requires a much longer time period for development. There are several different varieties suitable for growing in Illinois. However, when you purchase onions in sets from a garden store, you may not have a choice of variety because the sets are not sold under the varietal name.
Purchase firm, dormant sets and keep in mind that the larger sets (greater than a dime-size in diameter) are better used for green onions. Smaller sets produce large, dry onions that don’t usually bolt and form flower stalks.
Green onions can be planted close together and approximately 1 1/2″ deep. To produce dry onions plant them 2-4″ apart and only one inch deep. If you plant them 2″ apart, thin them when they get to be about 6″ tall so that the final spacing is 4″ apart. Keep in mind that whatever you pull is edible. Allow 12″ to 18″ between the rows.
Onions are shallow rooted and don’t compete well with weeds and grass that rob the plants of nutrients and moisture. Keep your onions weeded! If you are growing green onions and you want a longer white stem, pull some of the loose surrounding soil toward the plants (hilling) when they are about 4″ high. Dry onions are a different matter. Hilling can cause necks of stored bulbs to rot.
Harvest the bulbs in late July or early August when the majority of the tops have started to fall over. Allow this process to happen naturally because breaking over the tops early will result in smaller bulbs that will not store as well. Pull your bulbs early in the morning and leave them in the garden to dry out until the afternoon. The bulbs can then be moved to a cool place with good air circulation (placed on screens or hung up) for the next 2-3 weeks until completely dried.
The dry tops can then be cut until they are 1 1/2-2″ long. The bulbs keep well if placed in a cool, dry place. Generally, the more pungent onions will keep in storage longer than sweeter onions. Also, do not store your onions with your potatoes. Both will spoil faster.
You may have a problem with root maggots attacking the roots of the onions plants. An approved, labeled insecticide can be applied to the soil prior to planting if that has been a problem for you.
Remember to rotate the location of your vegetables each year in your garden and not plant them in the same location year after year.
According to Caitlin Huth, University of Illinois Extension Educator, Nutrition and Wellness, “Nutritionally, 1 large onion (about 1 cup chopped) contains around 60 calories, 14g carbohydrate, 3g fiber, and is a source of vitamins and minerals, including folate, potassium, and phosphorous. Like other veggies, onions are not a significant source of fat, protein, or sodium. Some research suggests flavonoids in onions may reduce risk of diseases, such as cancer and heart disease.”
Finally, if you are wondering why your eyes tear when you cut onions, they release a sulfur compound when they are cut. This gas mixes with your tears to form sulfuric acid, which creates the burning sensation.
There are many possible ways to deal with this problem, but one possible solution is to put the onion in your freezer for a few minutes before cutting it.
For more information, please contact your local Master Gardener or call or visit your local University of Illinois Extension Office.
Another great source of gardening information is the Extension website at

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