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tetrazzini

Starting onions indoors from seeds, in pots?

tetrazzini
9 years ago

Can onions be started by planting maybe 50 or more to a pot, maybe an 8" or 10" one, instead of in individual cells in flats? Would they get overcrowded and suffer root damage 2 or 3 months later when I separate them for transplanting? I'm going to grow 400 onions, and it'd be easier than in flats. I've bought leeks from a local nurseryman, and he just grabs me a clump from a bunch growing in a pot, which are easy to divide later when it's time to transplant. Can onions be handled the same way?

Thanks!

Comments (11)

  • theforgottenone1013 (SE MI zone 5b/6a)
    9 years ago

    Yes, you can start them in pots as you describe.

    Rodney

  • tetrazzini
    Original Author
    9 years ago

    Thank you, Rodney :)

  • planatus
    9 years ago

    In past seasons people have shared photos of their seedlings, and those working with flats are often in climates where the seedlings can spend quite a bit of time outdoors in strong light. I've grown summer leeks this way several times since you can plant them just about anytime, but I've gradually moved to 72-cell seedling trays with 2.5-inch deep cells for bulb onions. Thinned to one plant per cell, the seedlings grow on stress-free, don't need bumping up, and stiffen up nicely when the weather warms.

  • Charlie
    9 years ago

    As the forgottenone indicated, yes they can. I currently have leeks (of the same family) growing under lights in pots. When they are larger, I will separate them and transplant them out side.

  • tetrazzini
    Original Author
    9 years ago

    Good to know. I have a rack with fluorescent lights set up inside. At 72 cells per flat, 400 onion seedlings would need 6 flats -- a lot of space and handling. I'd rather grow larger numbers in pots, as I described the leeks above, but I wasn't sure if the young onions would survive root separation.

    I plan to put them in a cold frame as soon as possible, before transitioning them to the garden bed.

  • claydirt
    9 years ago

    When I started growing onions, I got seedlings from a local greenhouse in a little black tub, probably smaller than 3" x 5". There were 50 or 70 onions in it. So when I started growing from seed, I did the same thing.

    I use something about the size of a lunch meat tub, 3" or so deep. I "duck tape" clear tubs so roots stay in the dark. And write the onion type on the tape with magic marker. Drill half a dozen 1/4" or 2/8" drain holes in the bottom of the tubs. before you start. [I cut up a plastic milk jug, add water and place the tubs in the jug to water from the bottom.]

    You can only leave the onion seedlings in the tubs about 10 weeks before planting out. Dump the entire mess into a bucket of water, soak and shake them around to remove soil and separate, take your time. The roots usually come loose without a lot of root loss. Almost every one "makes it" through the transplanting.

    I just started about 400 seeds (60% just for green onions, I don't care as much about them) in well under 1 square foot of soil surface area. Grow light space is valuable...

  • tetrazzini
    Original Author
    9 years ago

    Thank you, Claydirt, for the detailed information:) I feel more confident about trying this now. Yes, grow light space IS valuable.

  • galinas
    9 years ago

    I use plastic window boxes.(22''X 7'') I plant in a grid 1''X1'', two boxes give me 12'X4' bed.

  • tetrazzini
    Original Author
    9 years ago

    You grow them under lights until it's time to transplant them outside? I planted mine yesterday, about 60 seeds per 4" pot. I hope they grow and transplant well.

  • dman86
    9 years ago
    last modified: 9 years ago

    I usually put a heating mat under mine so i can start them a little ealier.

    here is a link that might be useful: jubilee produce

  • psandqs
    9 years ago

    50 in an 8" pot is very thin. I've bought onion seedlings in 4-packs from SSE having about 25 in a 1½" or smaller cell. Each seems to support the other and no floppy plants. In fact, crowding has its advantages. The whole works comes out with one big mass of roots. No need to try to separate each one as those roots will already have been damaged and need replacing. Snip them off at about ¾" and they all come apart quite nicely. No need for the plants to try to repair a damaged root system and instead quickly make a new one. (Same applies to any bundles purchased from Dixondale or similar.)

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