Bella,

Have you grown a fall onion crop before from seed because I don't think it is possible in our climate?

Dawn

Hi Dawn:

No, I haven't ever grow onions from seed. Looking at OSU Extension and Texas A&M they refer to planting onions with seed, but do not give much other infromation. You are saying with our Okla climate it is not possible? Maybe I'll experiment. I have grown the same old stuff, the same old way year after year, and I am ready to become more adventurous in my old age (67). As always, thank you for your help, Dawn.
Bella

Bella, Almost all onions are daylength sensitive, which means that they start bulbing up when they start receiving a certain number of hours of daylight per day. For onions planted in Feb. or Mar., the daylength starts hitting the right number of hours in May or June, depending on the onion variety.

Short daylength onions start bulbing when the plants start getting about 10-12 hours of sunlight per day. Intermediate daylength types start bulbing when the plants are getting 12-14 hours of sunlight per day. Long-day onions need 14-16 hours of sunlight per day, so they generally only bulb up in the northern portions of the USA.

One reason we plant our onions as early as we do in our climate is to give them the maximum numbers of days in the ground to grow before the daylength reaches the right number of hours for bulbing. Since you get one 'ring' or 'layer' of onion for each green leaf on the plant, you want lots of green leaves in spring before the initiation of bulbing so that you'll get larger onions. So, I guess my concern is that your fall onions likely won't get that number of days of growing before cold nights arrive, and the daylength will be increasingly shorter, or the opposite of what they need.

If you start seed now, your plants will be growing in increasingly shorter amounts of daylight as summer turns into fall, etc. It is unlikely that your onions will bulb up, although you can use them as green onions of course.

So, if you go ahead with your plans, just be aware you may not get the desired results. I am not sure how the few daylength neutral varieties bulb up--in terms of what conditions initiate bulbing--but they might be your best chance for fall onions.

Dawn