Interesting Dan. Mine are still holding up well with daytime air temps in the high nineties. 130-140 in the shed. Don't expect sprouting until December.

Well, out of fifty onions, I was down to about fifteen, and two of those started to get soft after three months of storage with mean temps around 90F. I took the rest indoors, and things are good so far for the rest. These are, by the way, purple short-day. I believe that short-day lifetime is somewhat shorter than long-day.

You would think that temperature dependence of onion storeability is something that commercial growers and marketers would like to know.

Dan: Do your have a basement or cellar? I use to lay my root vegetables on the concrete floor in the basement.... when I had one... and that helped a lot.

We don't have basements - caliche. What is the temperature of your basement floor, and how long did the onions store successfully there?

After a one month cure in my shed, I store onions in my basement that is usually in the low 70s until September when it starts to cool down eventually reaching the low 60s over winter. I usually hang them from the ceiling in mesh bags but sometimes just put them in a single layer in shallow cardboard boxes if I don't have too many. I also segregate the ones that have thicker necks that didn't cure as well as the ones with thinner and use those first.

Humidity is also a concern. Onions like lower humidity but potatoes like it humid and I store both in the basement. I also store my garlic in the same area and if the humidity is too low the garlic will dry out before planting time. I have a dehumidifier in the basement and I try to keep everyone happy by setting it about 60-65%. I store some of the garlic that I know I don't need for planting stock in the fridge and it keeps well into spring.

They say that short day onions don't store well, but I wonder if part of the problem is the heat and humidity where they are grown. I googled this subject yesterday and didn't find much. ? Have you tried growing some long day onions to see how they grow and store.

I heard a story recently about a man in northern Pa who saved his apples over the winter in a junk refridgerator that he'd buried in the ground with the doors up. He covered that with straw. A big chest freezer would probably store more. Two even better.

I planted a second crop of potatoes to see if I could get seed potatoes for next year with a shorter storage period. I just found that they'd popped up yesterday. Would a second crop help with short day onions??

The issue here is temperature versus storage lifetime of short day onions. What is your storage lifetime, Lonejack? I have a number for 80-90F (3 months), and there are published numbers for 32-50F (6-ish months). I'm looking for a number at 76F, but a number at 60-70F would help.

I did find from UMn extension that, for vegetables in general, "Expect shortened shelf-lives for your vegetables as storage conditions deviate from the ideal temperature. This shortening of their life span can be up to 25 percent for every 10°F increase in temperature." If that's the case for onions, I'm looking at about 4 months at 76F.

Now, then there is this https://www.onions-potatoes.com/storage/onions.php which says that you can store onions hot or cold BUT NOT AT 20-25C. They say that's the temperature range that bacteria and fungi are active. Danger zone!!! That sounds to me like a bunch of crock. Bacteria and fungi are always going to be more active at higher temps, until they reach a survival temperature.

I have no storage problems with bacteria or fungi, just sprouting. They keep about 4 times longer hanging in the shed than ones put in vegetable drawer in the refrigerator. I know the Vidalia folks now keep them long term under controlled conditions but I don't know the specs. One theory is that sweet onions have a much higher water content than hot onions. The storage onions are hot onions, but I have no knowledge of how many months they will keep.. As a kid use to grow potato onions in Virginia. Those thing would bring tears to your eyes just by looking at them. Dug in late August they would keep until April. That is only a couple of months longer than I now keep sweet onions (Grano type). Granex which is the type grown as Vidalia don't keep quite as long.

Storage depends on type for me. I usually grow only intermediate day types Candy, Red Candy, Superstar. I harvest around July 4th give or take 10 days. Superstar usually lasts into mid October, Red Candy into November, and I think I've had Candy last into January before. I don't grow as many as I used to and try to plant only as many of each type as we will use before they sprout.

I keep a close eye on them when they are getting close to their storage life and chop and dehydrate some for making onion powder.

OK, that says 60-70F 3-5 months. I think I'm starting to get a complete picture. Thanks, everyone. Clearly there are other variables, like amount of air circulation and humidity. I'm concluding that storing them in an air conditioned house might get me 4 months instead of 3 in a hot shed. Not a big difference. Of course, air conditioning drys the air out too.

Now, I should say that lifetime for me is determined by when the top starts getting soft. Not sure if that's bacteria or fungi. Haven't run into any sprouting yet. I'm guessing that sprouting is a high humidity issue.

And yes, refrigerator storage is understood to be bad because of high humidity.