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Onions from seed!

Red onions grown from seed

This is the first year I’ve tried growing onion from seed, and they’re doing fine. Today, I pulled up one multi-planting of Red Wing to check ’em out. Multi-planting onions was also a first-time experiment, with 3-4 seedlings transplanted in one spot, at 12″ (30cm) in-row spacing. They’ve done a good job of pushing themselves apart, they’ve stayed pretty round, not flattening out where they touched.

Another thing I was a little concerned about didn’t come to pass. For around a month, the onion seedlings had already been under the usual 14-16 hours a day of fluorescent light on the grow racks, when I read about the possibility of daylength sensitivity at the seedling stage. When the amount of sunlight reaches a certain threshold, over 12 hours or so for long-day varieties, the onions move from leaf growth to producing bulbs. A couple of sources said that premature bulbing can be triggered by too much light too early on, even at the beginning seedling stage, and you’d end up with tiny, marble-sized onions after a season in the field. Other sources disagreed, but in any case, that didn’t happen here! Still, in future, I’ll start long-day onions under reduced artificial light…to be safe.

Multiplanted onions

As usual, the cracked surface of our clayey soil looks rougher than it is: it isn’t really hard, only a thin, dry layer with moist soil right underneath. Here, four out of five seedlings have pushed apart, rotating the stems outward, and grown into decent-sized…onions!



  1. I’ve never grown onions from seed so it’s interesting to read about your experiences.

  2. Le Petit Normand

    I have been looking forward for this picture. I did start my own onion from seed this year but due to the fact that a jerk smashed my planter were they were I lost all my seedlings …. I’ll try again next year for sure.

    Mike how deep did you plant them in the ground ?

    Do you think you’ll be able to cure some for winter storage as their leaf seems really green ?

  3. Le Petit Normand


    Sorry for my rough english but can you just tell me if I perfectly understood what you’ve done.

    You have just plant the whole plug with a few seedlings in it ?

    All that I read about onion started from seed said that you have to take each seedlings and plant them one by one after having trimmed leaf and roots .

  4. Le Petit Normand: Yes, we planted whole plugs with 3-4 seedlings in each, and left extra space between plugs. This saves time when transplanting, and also makes weeding quicker because you have less plants to weed closely around, and more space between to use a hoe. For onions, multiplanting probably works out best in a lighter, sandy soil, where the onions can more easily push away from each other, but even in our heavier, clayey soil, there was very little flattening where the onions pressed against each other.

    Multiplanting can work for all sorts of crops. I even tried it with broccoli this season. Yield per plant can be less, like, smaller onions or heads of broccoli, but overall yield for area used is the same or higher.

    I’m just starting to experiment with this method. You can read more about multiplanting in Eliot Coleman’s book, Four-Season Harvest.

    I’m not concerned with storage for these onions, there are a couple of varieties in small quantities as a multiplanting experiment!

  5. henok

    dear sir
    I m in plan of onion farming and i m in seek of some help of u r project and also some other good websites that i can read about plantation and pest controls.
    i thank u in advance

  6. 1440 onions : My Blog

    […] This is the look of 1,440 onions, starting out. These are 72-cell plug sheets, and the plan is to multi-plant four onions in each spot. Do a little multiplication—5 trays, 72 cells, 4 onions per—and the results are clear. Whether […]

  7. fran

    I planted real big white oniun sets on march 20th this year and thier already seeding off does anyone know why?

  8. Xavier

    I am afraid that the answer of your question is in your post. for onion set the smaller the better.

  9. ClaireyBear

    I am wondering about the day length sensitivities also- I’ve read some frightening things about exposing onions to too much artificial light as seedlings, but I keep all of my lights on the same timer and therefore they get 14-15 hours of light every day like everything else. Have you ever had any fail to produce larger bulbs because of over-lighting?

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