Onion Harvesting


I usually do this wrong and though I would get some advice as to how to do this right.

I have a fairly successful row of onions in this year’s garden, a few of the tops are starting to fall over but not that many yet, but frost/freezing weather is forecast in the near future (this weekend).

I am wondering what the best harvest plan would be. Should I pull the onions before any frosts/freezes? It will likely only be going down to 30F or so in the coming days then warming up again. Or harvest the ones whose tops have already fallen over but leave the rest. Or would it be better to knock the tops over on the remainder and wait? And another alternative would be to cover the onions overnight.

How does frost/freezing effect storage ability of onions. Do I need to get excited about a low of 30F or so?



I’d get them out. Frozen onions can turn to mush.


You can harvest onions anytime. Not as critical as say garlic. I found a couple onions in the garden this year I missed. They looked rough but were alive surprisingly. So they are biennial. I kept them is to see if they would flower. They should have flowered but never did. Best to pull onions out and replant for seed in the spring, if you want seed.


For storage, I’d say it’ll take a long time curing if you pull them with green tops, but they ought to cure


Leave a few in and report back to us. That would be helpful info as to if we can leave them in. My onions have been done for months now though.I agree about the curing, just dry them well.


Onions form bulbs according to the number of daylight hours (which depends on latitude) and those are diminishing now so they won’t get any bigger.
If you want to use them, I agree w/@Chikn that it is time to pull them. Not sure where you are but zone 5 seems pretty cold and onions are not one of the cold hardy alliums.
If you want to overwinter them for seed, you def have to protect them from freezing. Not sure how much mulching you would need for that. Lots probably.
I don’t wait until all the leaves are dried or fall. The neck will soften when it is time to harvest. I cut off all but 2" of the leaves and leave the roots on to dry faster and then cure them in a dry place. If the neck is still firm you can still pull the onion and just use it first.


Are there onions that would be hardy in zone 5? Any recommendations or sources would be greatly appreciated.


@Anne, not sure what you mean by hardy, but if you mean will grow and size up bulbs, yes, there are lots of onions which will do this. If you mean over-winter the answer is also a qualified yes, but not sure why you’d do it.

Onions are biennials, so they will go to seed in their second season. Over the years, I occasionally miss an onion or two when harvesting, and the typically survive up here and grow again the next spring. But they are not in any condition for human use, except to make seed for future years perhaps.


Hardy is not the correct word. I should have asked about perennial onion.


Thanks all for the thoughts.

My main concern in all this was getting the most storage life and quality out of the onions. I know a hard freeze softens the outer layers of the bulbs and make them unfit for storage (don’t ask how I found this out). Really what I was trying to figure out was if a mild frost or freeze which doesn’t cause any noticeable softening of the bulb still reduce storage quality.

Generally I have noticed that pulling onions before they start to wind down (tops falling over on their own) seems to lessen storage. Since I am in a short growing season area, I often have to decide whether to pull still growing onions before a freeze or chance that they make it thru unharmed.

I’ve decided to do an experiment along the lines of what Drew suggested (and hedge my bets on the weather some too), and leave some of the onions in the ground over this cold snap. I’ve pulled and am curing all the onions which started to show signs of winding down their growth (tops falling over). I’ve bend over the tops of the other (to give them a hint), and will cover them at night for some thermal protection. It’s only forecast to go down to 29F or so, but that could easily end up at 22F too.

Guess I will see how this goes.


What kind of onions are these, that are still growing in Sept?


Lois, I grow a couple varieties of onions and leeks. The main onion crop is Ailsa Craig a big sweet onion from Scotland which stores well (for a large sweet onion that is). Been growing those for 10+ years and they are our favorite onion. Also growing a few storage onions this year, to try and have onions next summer. And leeks. (don’t recall the variety on the leeks and storage onions)

Its not that unusual to have onions still growing here. Our growing season is shorter than many places, so the onions did not get out in the ground until end of April/May. And we have only had one mild frost so far, with temps back up in the 70’s after that.


I’ve thought of growing those, but I have such good crops with Candy, I stick with it


Candy is the best!!!


Hello Anne, doesn’t look like your question got answered. YES! There are perennial onions and here is a growing guide more geared for VA where these suppliers are located. How the culture thereof differs where you are may be found at your county extension agent’s office.


Thank you for the great information. Now I just have to find some of those onions.


I ordered from them and they still have some in stock. They also have other perennial onion types. Their culture is similar to garlic so if you have grown garlic it would be about the same (depth of planting, mulch, time of planting - which is coming up pretty soon for the colder climates.) I’m guessing y’all would have to plant a little deeper and mulch a bunch more than they recommend for here in VA)


Thanks again!


I guess I missed the direction of your question Anne. Yes there are perennial onions, I have even tried growing them a bit up here.

One thing that I found was that the multiplier onions (aka walking, Egyptian onions) were only good to eat at certain points in year. Outside of those time slots, then tended to be bitter and not that good. Perhaps not an issue in longer, warmer seasoned areas, but here it meant there were only certain times those onions were usable.


I think the Egyptian walking onions (Allium cepa var. proliferum) are dif than the multiplier or potato onions (Allium cepa var. aggregatum), so I’m not sure if your comments apply to both.