Onions can be harvested at any stage during their growth cycle. Harvesting onions early will give you small, green onions, and harvesting at the end of the season will give you large onion bulbs. You may think that harvesting mature onions is a straightforward process. However, there are tips you should follow to ensure that you get a longer shelf life out of your onion harvest.
Pull young onions out of the ground at any time for the taste of young, green onions. If you want to harvest mature bulbs, continue on to step two.
Wait for the onion tops to turn brown and fall over to the ground.
Grab hold of the tops down near the onion bulb, and gently pull the onion out of the ground. Shake off any excess dirt from the bulb.
Lay out a sheet of newspaper or tissue paper in a warm, dry area. Lay the onions out on the paper, and do not cut the tops off yet. Allow the onions to remain on the paper for two weeks. Onions are dry when the outer skin becomes dry and papery, and the neck of the onion begins to shrink.
Store the dry onions by braiding the stalks together, securing with a string and hanging in a dry location. Alternately, cut the tops off and store the onions in a mesh bag or a box with air holes drilled in it. Keep stored onions in a cool location.