Because of their versatility in the kitchen and ease of growth in the garden, onions make a perfect project for any home gardener. Like any other vegetable, onions start from seeds and eventually grow into an edible plant. If you want to have a self-sustaining garden, you need to collect seeds from your onion plant and store them until the next growing season. Since the seeds don't grow in the actual onion, the process for harvesting the seeds can be confusing. But while it may seem difficult, the process is actually as easy as using a pair of scissors.
Wait for the flowers on the onion plant to wither and die. You may also notice a few fallen seeds on the ground beneath the flowers.
Clip the flowers with a pair of sharp shears. Place them immediately on a baking sheet to minimize the number of fallen seeds.
Leave the flowers on the baking sheet and store them in a cool, dry place for three weeks. The flowers and seeds will dry out during this time.
Shake the flowers after the drying period to remove the seeds. Separate the seeds from any other flower debris.
Put the seeds in a paper bag and store them in a cool, dry place until you are ready to use them.