Collecting Onion Seed

It’s onion harvesting time in South Carolina, and my Red Creole onions bolted weeks ago. When I harvested the last of my crop this past week, I decided to let five of them remain so the flowers could mature and produce seed. Because Red Creole onions are an heirloom variety (not hybrid), I want to collect the seed to plant next year.

The picture above shows my Red Creole onion flowers. Onions are biennials, setting flowers and seed in the second year. However, my onions produced flowers the first year. (I planted the onions from seed October 1, 2012.) I think it’s because we had 80 degree weather in January (after a couple of frosts), so my onions thought it was summer. Then we had several more frosts after that, so my onions thought it was the second winter. Strange, isn’t it?

Well, back to my onion flowers. If you look closely, you’ll see that one flower head contains dozens of small individual flowers, each of which will become a seed pod as the flower dries out during the hot summer days to come.

Onion seed pods (photo credit:

Onion seed pods (photo credit:

When your onion flowers are dry and you start to see the black seeds over most of the flower, it’s time to harvest. Cut the flower head off, leaving a few inches of stalk. Place the flower heads in a paper bag, close it up, and keep it in a cool, dark place for several weeks.

Once the flower heads are completely dry, it’s time to separate the seeds from the pods. This can be done in a couple of different ways.

  • While the flowers/seed pods are in the paper bag, shake the bag to loosen the seeds. You can manually rub the pods inside the bag, as well. Then empty the bag into a fine strainer to separate the seeds from the “chaff.”
  • You can also empty the bag into a fine strainer without shaking the bag first, then rub the pods to remove the seed.

Either way you separate the seed from the chaff, store your seed in an envelope or paper bag in a cool, dark place until the fall planting date for your zone. Here in Zone 8, it’s October 1st.

Please remember that onions produce flowers the second year (unless you have the crazy winter we had here). So don’t plant all your seed the first fall; save some for next year while you’re waiting for your onions to produce more seed the second year.

By sacrificing the harvest of a handful of onions, you’ll get hundreds of seed to keep those onions coming season after season.

Have you ever saved your onion seed? How did you do it?

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