I need information about planting long day onions in the fall in my zone 5.

Would the plants survive the winter?
Has anyone observed onions surviving winter in zone 5 or colder?

Funny you should ask, Gerry !

First, I would just say that I have often had onion plants sprout back up in the spring -- ones that I missed pulling somehow, even ones that were leftover onion seedlings that I started, never got around to planting because I couldn't find room, and just threw out on the garden in the fall. Those were all unintentional, but nonetheless made nice green onions in the spring; most bolted after a while and so didn't make too much of a bulb, but some did, if left to grow long enough. That didn't usually happen because they were in a place where I wanted to plant something else so they got pulled out.

In the spring of 2014 I had the idea of buying more onion sets than I needed (I always start a lot of onion plants from seed, but until this year - 2015 - I've always felt the need to kind of hedge my bets by planting sets as well), store them in the crisper drawer of the fridge, and plant them in the hope of harvesting some onions in the fall. So, on Sept. 7th I planted the sets, and they promptly started growing.

It took a while, but I finally came to the realization that those onions were never possibly going to bulb up, because they were long-day types; I harvested some to use for scallions, then as the weather got colder I set up a 'low tunnel' of plastic over PVC hoops over them. I continued to harvest scallions until the winter got really settled in, and then just let them be until spring. Once I could get back into that area I saw that the onions had apparently survived, and as the weather started to get a bit warmer (probably in March) I removed the plastic and just let them do their own thing. Had onions to pull for scallions, and then saw that the plants were beginning to form bulbs so I left them alone again for a while. I finally pulled all the ones that were left in mid July, and while probably about 1/3 or so of the plants had bolted and did not make nice onions, many of them had nice large bulbs and small "necks," so suitable for storing.

So... now that you've had the long version, the short answer is: Yes, onions absolutely will survive winter in zone 5 or colder! (I'm in the southern part of the upper peninsula, which was previously zone 4b but was changed to 5a when the USDA revised the zone chart in the fairly recent past.)

I don't think they really would need the low tunnel covering... but if you want to harvest some green onions as long as possible and then again as soon as possible in the spring, it makes them a lot more accessible.

Thank you, so much, Sandy. Next week I will be planting garlic and onions.
I have more time in the late summer and early fall. In the spring and early summer, I have too many garden chores and duties to do.

Gerry

profesora said:Thank you, so much, Sandy. Next week I will be planting garlic and onions.
I have more time in the late summer and early fall. In the spring and early summer, I have too many garden chores and duties to do.

Gerry

I so agree about having more time towards the end of summer... whew, kind of gets to be a whirlwind of things that HAVE to be done for a while there!

This seems rather early for planting garlic, though... is late August the time that you normally plant it? and, if so, does it start growing tops before winter sets in? I'm really curious about this because I've always read that it should be planted later, so the roots start developing but no top growth, which will get killed by the cold -- is this yet another "myth" ? (I've also read that we can't grow Creole garlic in the north but proved that one wrong this past year !

At any rate, best of luck with the onions... are you planting sets, or plants? (I'm kicking myself now, after getting pretty nice onions from the experiment last fall, because I have neither to stick in the ground at this point... )

I usually plant garlic in late September, and after what you said, I will plant a few now, and plant the rest late September.

The onions are sets that I grew from plants. If this works, I will not plant onions in the spring when I have other chores that have to be done very early.

I plant all my garlic here in NE Mississippi (zone 8b) between mid-October and early November.

In zone 5, we also plant garlic in late summer, which is late late September. We usually have our first frost by October 15. Last year, instead, we had an ice storm.