Starting Onions Indoors

Onion Flats Under Lights

Onion Flats Under Lights

Here are three flats of onions I planted on February 8th, 9 days ago. Most of the nearly 1,600 seeds are sprouting nicely in flats in the basement. The flats are on a heat mat and lit with various LED grow lights we have accumulated over the last few years.

The onions are growing in a commercial potting soil. I used to make my own potting soils, but I’ve found the commercial mixes to be much more reliable in giving me good strong root growth, and they are certainly a lot easier to work with. Mostly, I’ve been using Jiffy Mix. Jiffy now offers organic mixes and they sell it in large bags, which I like, since I go through a lot.

Copra Onion Seedlings

Copra Onion Seedlings

These seedlings are Copra onions, a very reliable commercial yellow hybrid storage onion that I’ve grown many times. Also planted is Red Bull, a red storage hybrid, new for us. That’s it for the hybrids, the rest of the crop includes, Borretta Cipollini, an old time heirloom flat Italian onion that we’ve only grown once before, and Rossa Lunga di Tropea, a torpedo shaped red Italian heirloom that we have not previously grown.

Finally, we have just over 300 Lincoln leeks seedlings. Lincoln is an old American heirloom that normally does well, although I had a leek crop failure last year. I know my mistake and I hope to have a good leek harvest by replanting my leeks to another outside bed for some growth before I plant them deeply in their final home.

I’ll start fertilizing the flats, soon, and transfer them upstairs to a south facing window to free up the heat mats for tomatoes and other crops that also need the heat to get started.

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6 Responses to “Starting Onions Indoors”

  1. Hi Noel, Where are you buying Copra onion seeds? Johnny’s seeds stopped selling them. I’ve got some interesting onion seeds from Nichols Seeds, including one called Exhibition that claims to produce good, big onions up to 2 pounds. We’ll see.

  2. Noel says:

    Hi Henry. These were from Fedco, but there are numerous sources on the Internet.

  3. Susan says:

    Can you give a little more information about leek growing. Even growing from starts, mine never get very big. I started some from seed this year indoors.

    I’m growing in the mountains of western North Carolina.

  4. Judy says:

    Susan, we have been using a method of Eliot Coleman’s to get big leeks. It requires a 2nd transplant. You let the first planting or transplanting of leeks get about pencil size, then transplant those to 9″ deep holes. Last year I tried to cheat and planted them right from the flat. They were too small and I had a failure, but the previous year they were great. Here’s a link to an article about Eliot Coleman. Scroll to the bottom for his leek method: Noel

  5. Janet Gremban says:

    Noel. When your onions start getting tall and flopping over do you give them a haircut?

  6. Noel says:

    No. I don’t trim them. I’ve read it’s better not to. More energy goes to the root rather than having the plant work to put out more leaf.