When to put leeks and onions in the greenhouse?

12 years ago

This is my first year growing a very large number of leeks and onions. My seedlings are 3 weeks old now, about 4.5" tall, and have been trimmed 3x already. They are showing 3 leaves. I have two outdoor greenhouse which i built this year in which i already transplanted my broccoli, cabbage and cauliflower. I live in extreme se PA, and our weather has been in the mid 50's each day and around 38-45 at night. Our long range forecast is no different. 50-60 degrees during the day and temps around 38-48 for lows. Do i really need to let my onions and leeks grow for 8 weeks indoors before i set them out? My greenhouses are very warm during the day, and retain a lot of heat during the night. On the few nights where it dropped below freezing, my greenhouses were not the least bit affected. I already have spinach and carrots a month old in one of them. That's how warm of a winter it's been.

Sort by:Oldest

Comments (2)

planatus
12 years ago
Good question. We share similar weather and I'm having to shift my onions and shallots around daily because the more light they can get, the better. If I had a greenhouse I'd move them out there today, with some concerns about the cold this weekend. I'd want them to stay about 45 at night if at all possible.

You need to be trimming back the tops every few days to 4 inches or the plants will topple over and won't bulk up. The plants' progress will pick up as days become longer because they run on sun.
Mark
12 years ago
This is absolutely NOT TRUE.
"You need to be trimming back the tops every few days to 4 inches or the plants will topple over and won't bulk up."

This is probably my 16 year growing and I rarely trim my onions or leeks in the flats and I grow about 1/2 acre of them. Maybe I do it once or twice for the 2 months they grow in flats.

Planatus, your alliums are most likely toppling over because they are not getting enough light and/or you seed too thickly.

As for the OP's question. If you think the onions are big enough and you have a good bed to transplant them into, go for it. The only thing you gain by keeping them in flats is more control over the temp and less weeding while they grow.
Related Professionals
West Milford Landscape Architects & Landscape Designers · Arlington Landscape Contractors · Peabody Landscape Contractors · Coram Landscape Contractors · Englewood Landscape Contractors · Gallatin Landscape Contractors · Goodlettsville Landscape Contractors · Pacifica Landscape Contractors · Roswell Landscape Contractors · Country Club Hills General Contractors · Gloucester City General Contractors · Kemp Mill General Contractors · Olney General Contractors · Orangevale General Contractors · Spencer General Contractors