onion seedlings: trimming height and transplanting Qs

dab07March 30, 2008

I'm growing onions from seed and they're under lights right now. I started them 3 or 4 weeks ago and they're about 3 to 4" tall. I've read that you can cut them down to about 3" before planting, but I'm wondering if I can trim them now. They're almost touching the light, which I can't raise any higher.

Would trimming them inhibit their growth or otherwise harm them? If so, I'll have to figure out something else...

Also, at what point can they be transplanted, both in terms of their age and the temperature outside?

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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

You can trim them at any time and even multiple times before transplanting. The trimming is done to strengthen the stems and roots by forcing the growth of a new layer on the bulb which then becomes the next new green top. ;) The more frequently you trim the more the layers develop. I do all mine weekly at least to 3".

Planting - they want 50 degree soil temps - that is usually about the temp shortly after the ground can first be worked in the spring. They will tolerate light frosts with no problem.


    Bookmark   March 31, 2008 at 12:42AM
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Thanks Dave. Can they be too young or thin to transplant even if the outdoor conditions are OK? They're only about 3 weeks old. I'm wondering if it's more advantageous to leave them indoors under lights or transplant them ASAP.

    Bookmark   March 31, 2008 at 12:13PM
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This thread is of interest to me, as well. I'm going to throw in another variable...the container! Can onions do well in containers? I currently have two varieties: Red Robin and Yellow Granex Sweet. What size and depth of containers would be best suited for these? Thank you in advance!


    Bookmark   March 31, 2008 at 5:06PM
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Thanks for the info. I definitely pushed the season this year and my onions are huge! And I can't plant for at least 3 weeks.

    Bookmark   April 1, 2008 at 5:15PM
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annebert(6b/7a MD)

You could keep your onion inside a week or two longer and feed with dilute fish emulsion (or whatever fertilizer you use) to get them bigger before planting out.

    Bookmark   April 4, 2008 at 8:45PM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

Can onions do well in containers? Sure. Many grow them in Earthboxes but most any container should do. Shallow ones like window boxes would be best I think as they are shallow planted so why waste all the soil in a deep container? ;)


    Bookmark   April 4, 2008 at 9:04PM
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