These onions were planted two years ago. Onions are a biannual, which means they grow two years in a row and then they bolt the second year snd you save seeds. In Colorado I planted my onions in the ground in the fall only to see them spring up in the spring/summer time. I started with an onion bulb, not the seed The first year you do not see these flowers better known as “bolting”. Bolting is when the plant continues its growth and has flowers with the seeds in them. If you are going to start with the seeds, plant in the early spring inside if you live in a cold climate and replant in May.
After cutting the flower off from the stem of the plant. Allow it to dry on a cheese cloth or other clean cloth. Paper towels will work also and place the flowers on a cookie sheet with the cloth. The flower will need to dry. It will take about three weeks. You will know that they are dry when the little black seeds fall out.
To fully shake the seeds out just gently tap on the flower on the clean cloth or you may place the flowers that are dry in a paper bag and shake them in there and the seeds will dispurse out.
When you collect the seeds place them in a glass jar or an envelope. Make sure that you put a date on the jar or envelope. Don’t place in a plastic jar as there seems so be some problems that could occur with the seeds in the plastic container.