How to Harvest Onion Seeds

• 1). Watch for your onions to flower. Onions are biennial plants, meaning they flower every two years. As such, many onions will not flower during the course of a normal growing season. Occasionally, when the weather during summer gets cool enough for the onion to grow dormant and then warm enough for growth to begin again, the onions are "tricked" into bolting, or producing flowers.
  
  
• 2). Examine the head of the flower for signs it is fading. The head of an onion flower is shaped like a large globe and is comprised of lots of tiny flowers. Each flower will produce a number of seeds. As the seeds develop, each small flower will begin to wither and may even begin to drop some seeds. Once most of the flowers on the head have died, clip the head off.
  
  
• 3). Put the onion head in a cool, dry place for at least three weeks. At this point, you can hang the onion heads to enhance drying. It may be helpful to dry the seed heads over newspaper to catch seeds that may begin to fall.
  
  
• 4). Remove the seeds from the dried flowers. Many of the seeds will begin to drop as the flowers continue to dry. You'll need to physically remove some of the seeds. To do this, hold the dried heads over a piece of newspaper and gently roll them between your hands. The seeds will fall onto the newspaper.
  
  
• 5). Place the dry seeds in an envelope and store them in a cool dry place. If kept dry, these seeds will last for a year. If you wish to keep them longer, store them in a jar with a desiccant.