Onions come in different sizes, shapes, colors and flavors, from mild and sweet to hot and strong. A full-grown onion plant has roots, bulbs and leaves. The leaves are long, thin and hollow. They stand straight up and thicken at the bottom to form a bulb.
Growing onions is easier than you might think. They're the perfect crop to tuck in between other plants or in corners of garden beds.
There are two methods of growing onions: from seed and from sets (small bulbs). Sets are easiest for beginners, although growing from seed is not difficult.
Onions are biennials, their life cycle is two years long. But they are usually picked during their first year before flowers form and the bulbs stop growing.
Onions grow best in loose, fertile soil. They can grow in many different climates.
In cooler climates, onions may need fourteen to fifteen hours of daylight to start forming bulbs. In warmer climates, onions can begin developing bulbs with fewer hours of daily sun.
Barbara Fick, an extension agent at Oregon State University, says a faster way to grow onions is to plant what are called sets.
Barbara: "Well, onion sets are actually small plants, versus starting with a seed. So when you have a set, onion set, it actually is, you know, the small bulb. So it does not take as long to grow."
Organic material like compost or leaf mulch can help onions grow in heavy soil.The bulbs can be pulled from the ground once their tops have dried and fallen over. Onions can be stored for months. But Barbara Fick says stored onions need to be cured first.
Barbara: "Curing is a way of making sure those leaves on the outside are nice and dry."
Here are some directions from editors at the National Gardening Association.
First, dry the onions in the sun for a day or so. Then bring them out of direct sun for two to three weeks. Spread them out in any warm, airy place that is covered. Or cover the onions with a light cotton sheet held in place with stones along the edge.
The sheet will keep the sun from burning the bulbs. Don't worry about rain. And do not use a plastic or canvas sheet. Heavy coverings will trap moisture and keep the onions from drying fully.
Turn the bulbs a couple of times to help them dry evenly.
After curing the onions, you can hang them indoors in mesh bags to dry even more. There should be no wet spots on the onions when they are put in storage. Editors at the National Gardening Association say the longer onions are cured, the better they will keep.
Some people cut off the top leaves before curing onions. If you do that, do not cut the leaves any closer than two and a half centimeters from the bulb.
Growing onions takes patience, since all the action takes place under ground. If you can provide a rich soil and a full day of sun, you can grow a good sized onions.
At last, how to do harvetsting and storage?
Onions are fully mature when their tops have fallen over. After pulling from the ground allow the onion to dry, clip the roots and cut the tops back to one inch. The key to preserving onions and to prevent bruising is to keep them cool, dry and separated. In the refrigerator, wrapped separately in foil, onions can be preserved for as long as a year.
The best way to store onions is in a mesh bag or nylon stocking. Place an onion in the bag and tie a knot or put a plastic tie between the onions and continue until the stocking is full. Loop the stocking over a rafter or nail in a cool dry building and when an onion is desired, simply clip off the bottom onion with a pair of scissors or remove the plastic tie.
Another suggestion is to spread the onions out on a screen which will allow adequate ventilation, but remember to keep them from touching each other. As a general rule, the sweeter the onion, the higher the water content, and therefore the less shelf life. A more pungent onion will store longer so eat the sweet varieties first and save the more pungent onions for storage.
* Original source: Planting Onions in the Garden