Onions are one thing I’ve never tried from seed. I usually buy ‘sets’ which are onion bulbs that I direct sew once my soil is warm enough.
What variety(s) have you started? Is it one you’ve planted before?
Rosa DiMilano, a red one that is an excellent keeper, and Stuttgarter that I actually saved seeds from.
I also ordered Stuttgarter onion sets just in case the plants don’t start well.
The Stuttgarter are also excellent keepers. The ones I have in the garage are still in great shape, juicy, crisp, and some are just barely starting to show a green shoot in the center when we cut them open.
I’ll likely have to break down and buy some before next season’s crop comes in, but what a great feeling of satisfaction knowing that they were so successful.
I plant sets....and cut the greens all through the growing season. $3 at Walmart.
I take a large pot--12 Inches diameter is good--put some oak leave mulch at the bottom and and fill within 2" of the top with compost or your seed medium (It will settle!) Sprinkle your Leek seed widely on top, push down for good contact. Sprinkle a small amount of compost over the seed. Lightly water. If going outside cover with some gardening fabric and secure it with some cord or twine. (Squirrels and heavy rain1) You can do this on the back porch or in a potting shed or just leave it outside somewhere sunny in the garden or near the faucet where you will remember to occasionally water it (if its dry!) Depending on when you intend to plant you can leave the pot outside all winter or do this in early spring.
Sometime in early spring remove the cover and check for sprouting. Once those grow to about 2-3" snip the tops and remove the snips from the pot.This will force them to start side branching. Fertilize lightly after you get 2 or 3 leaves. (The top snips will usually have the seed hanging on to it...the snips do not seem to die, but linger on and look like new sprouts! Put the pot on its side if you can and snip the tops! ) Wait a few days....fertilize lightly...maybe 50% dilution of miracle grow or equivalent; 2 or 3 weeks later more heavily. Keep snipping the ends as they get taller each time a bit higher. (Thin if they are too crowded.) In a month or so you should have a pot filled with plant-able baby leeks. When ready to plant de-pot, divide the clump and plant in trenches along with good fertilized compost.
Right now I have about 10 overwintered Blu d' Solaise leeks growing in the garden that I started sometime last May. (No covering this winter at all... just some mulch... More violet colored than blue!)
ONION SETS: I think that you could probably do easy onion sets in pretty much the same low maintenance way if you start early. (I would do this on the back porch late winter though!) I have tried planting bublete annual onions and have never gotten good results. (The bundles of sets is the better way.)
This would easy for people with potting sheds, you, Augie, Pollard!