For spring planted onion seed from a source with a commercial grower orientation and seed selection check out Stokes up in Buffalo. They have a website but also can get you a hardcopy catalog. The brief cultural advice given with each type of seed can be really valuable.

You can grow good cooking onions if sown directly in the very early spring and thinned properly. Feed abundantly and make sure soil moisture is uniform all season over a well drained bed. Northern commercial onion growers rely on spring planting to a great extent and it works for them.

Quality will be spotty if soil nutrition and moisture vary over the growing season. Best quality is from stable conditions. True for all alliums regardless of when they are planted or transplanted. Only let them dry down as they reach the final stages before harvest.

Fall planted alliums need special care to assure well drained beds, which usually means somewhat raised planting rows.

Ailsa Craigs are a huge, sweet and juicy onion, but their storage is poor - about one month - so only plant what you can consume or freeze quickly.

My favorite is Copra, a beautiful medium sized onion (3") that is a sweet but more pungent than Ailsa Craig and stores very long - sometimes through the winter.

TomNJ/VA

Definitely agree about Copra. I expect mine to store through the winter. Available as seed or bunches of plants you have your choice of growing methods. I expect that you can grow your own sets from them too, if you are willing to devote a small patch to planting them thickly. I routinely plant back any that do not size up well the first summer and get them to size up nicely the second one, with very few to no bolters; so the set option should work just fine.

Edit: I do not store my Copras cold, but rather at just about room temperature in one corner of my kitchen. That may be why they don't bolt when planted back the second spring. They keep every bit as well for me as the yellow potato onions do, which are treated the same way. In fact they seem to keep even better than the white potato onions. I generally braid all three types, with big and little Copras in separate braids.

Copra definitely sounds like a good option. I will definitely look into it.

What is involved starting seedlings indoors yourself? It looks like you can just throw a handful of seeds into a small pot and let them grow in a clump.

Would the Ailsa Craigs really only store a month? Thats a shame. Would Copra do well in Southern NY? Maybe I should just stick to the Walla Walla, I know those do well, make large sweet bulbs, and store several months. Copra kind of seems like a generic grocery store bulb.

How about King Richard leeks?

For me Walla Walla does not store well but the one time I grew Copra it also did not store as long as it was reported to. I have best luck with Candy for long storage.

I grew both King Richard and American flag leeks from seed this year and I preferred KR over AF because they were shorter DTM and the bulbs seemed to be more tender with less core. Next year I think I am going to try to start just the KR about 15 seeds once a month from January until early April and plant out from late March until late June. This should get me fresh leeks to harvest from June until October.

For me Copra is the best keeping onion I have ever grown except for yellow potato onions, and even then Copra keeps very nearly as well. I have no problem keeping them into the next summer from harvest the previous year. All my alliums are stored in a corner of my kitchen which though a bit cooler than some rooms, never falls below 60-65 degrees. The key of course is a solid curing process. I usually braid the onions on the racks once the tops have wilted and dried out nearly completely, and leave them there until completely dried and well skinned. The screen porch where I cure my alliums gets hot during the summer. I think that helps to heal the bulbs. I do not let the onions stay in the ground until the tops have totally dried off either, but try to dig them once the tops start to wilt significantly. Generally that is about the same time as the tops on the multiplier onions go down. I also cure all of my alliums out of direct sunlight and generally with the heat of the end of summer. That seems to work pretty well for the few cipollinis I grew last summer too. Those like the Copras were from plants and they matured in late July/ early August.

When I was growing up we cured potatoes and onions on the north side of an empty corn crib. Summer heat, good ventilation, shade and protection from rain. I try to imitate that and the west facing screen porch does a good job. Works for potatoes and tulips, too, but by the time sweet potatoes are ready to dig around here it is starting to get a bit too cool out there.

Can you describe your seed starting process for the leeks? I was hoping to just grow a clump like they do outdoors for transplants.

I will look into Candy, thanks. I hope the intermediate day onion would do well in NY? Don't want it to bulb up too soon.... It does look like the best, huge sweet onions that store well and are reliable.

For starting both leeks and onions from seed my process is the same.

I use 2 lb. yogurt containers which are about 5" deep to allow for long root growth. I start 10-12 weeks before my plant out date. I fill the containers with my pre-moistened potting mix (Promix BX) then as evenly as possible distribute about 35 seeds max in each container and then cover with a thin layer of the pro mix.

I put the containers on top of my basement freezer for some extra heat and monitor daily for sprouting and when the first sprout pops up I place them under my T8 shop lights about 1" from the bulbs. The plants grow fairly slowly for the first month or so. Initially they don't require very frequent bottom watering but as they grow I have to water more frequently and I also use a water soluble fertilizer diluted to 1/4 strength about every 2 weeks.

At about 6-7 weeks they should be around 5" tall and growing their 3rd true leaf. The seed leaf also begins to yellow and wilt at this point. I start giving them haircuts about every 5 days to keep them from getting too leggy and falling over. I try to keep them in the 4-5 inch range.

When planting out I just invert the container with my hand under it and the onion/leeks come out in one big clump. I then swish them around in a bucket of water to wash off the potting mix which makes the plants easy to separate.

Sounds perfect, thanks.

When do you transplant them out? I want to put the leeks out later than the onions so they are not exposed to temperatures that make them bolt. Expected plant-out date this year had temps as low as 20, and many bolted. What kind of hardening off do you do? Thanks! :)

Here I plant them out sometime in late March after hardening off for about 10 days. But it also depends on the extended forecast not showing anything too cold. Mine are planted in raised beds so not too difficult to cover if needed especially since they are small and planted in a 5" deep trench.

Yeah late March here is likely to be frozen snow covered ground. So I guess, as soon as the ground can be worked.

Frost goes out here in Minneapolis, somewhere in mid-April on average. I usually get my plants from Jungs in Wisconsin who send them out towards the end of April; so I plant my onion plants as soon as I get them. I would do the same for leeks, but I don't grow leeks. Onion sets and potato onions would go in as soon as the ground was frost free and properly worked up, which in some years is toward the beginnings of April. I don't generally worry about light frosts on that kind of early planting, although heavy frosts into the lower 20's are a concern.

Hi Peter; I just thought I would add my 2 cents worth. my garden is zone 3, 3000 ft elevation 51 degrees latitude. I grow walla walla they grow well, store till Christmas, I also grow Expression (substitute for Candy?) they grow well and store longer (March) My storage onion is Hendrix (from Stokes) this past year they stored till the Walla Walla's became useable in July. All my onions I start from seed March 31 and set out May 15. For Leeks I have settled on "Autumn Giant" from William Dam Seeds in Canada. I start them the same time as my onions, but they are not as large when I set them out and I can let them stay in the ground till late September or early October, they never bolt, and are a very good leek in my opinion. Hope this helps. Chic

Thanks for the suggestions.

I am thinking starting the first week in February for the first week of April planting. Maybe even mid February... this Spring everything grew very fast! And I had rootbound issues and had to plant early. Except the peppers. I'm lucky the weather agreed. I don't want them to get too big and wind up bolting due to transplanting into cold temperatures too large.

Do they ever get damping off, started in a large container? I will use the seed starting mix I used last year that gave me no issues.

I have row covers I can use also for the cold nights.

Hi Peter;

I start mine indoors on a heat bed then transfer them under lights, they haven't ever damped off on me. I give them a haircut periodically which helps them to bulb out the onions are usually about 3/16 of an inch in diameter, and the leeks about 1/8th of an inch when I set them out. Mid may here has cold nights below freezing 'til early June, so far every thing works good. Chic

Chic, do you grow them in a single pot like LoneJack?