What caused my Walla Walla onions to be hot last year?

I have grown onions for many years, and have had great success with Walla Wallas- but last year they were excessively strong and hot. I am not scientific about soils, so can't tell you what it was- I add amendments such as compost, coffee grounds, etc. several times during the off season. I have earthworms so my soil must be good! Any help will be appreciated. I just got a 9 pack at Lowe's and will separate them and plant them soon, so if I can get any info before then it will be good.

I think I just read somewhere that it has to do with even watering?

Maybe they weren't Walla-Walla's.

I don't think it is either of them- I buy plants from nurseries that have labels-(Bonnie plants) and I have irrigation that keeps watering regularly. I'll just try again and see what happens.

Bonnie usually labels correctly BUT customers switch tags around at the nurseries all the time. Even a major grower like Bonnie can get a mislabled batch of seed from their supplier. Onions will be hotter when growing in hot dry conditions.

Most onion plants in stores here are supplied by Dixondale. So the 60 bunch crates are set out side by side, Customers take a bunch out & then put it back in the wrong crate.

The labels were not mixed up because the truck unloaded them while I was there--the first of the season. Most likely it was the heat as Farmediill suggested. And if it is that I can't do anything about it. There's nothing I love more than a sweet slice of onion on a sandwich, but that may be up to Mother Nature! If I fail this year than there's always the Farmers Market!

While it is true hot dry conditions can increase spiciness of onions and peppers as well as soil type it is more likely you didn't have Walla Walla onions.

I have grown many a starter plants and even fruit trees with tags on the trees that were labeled incorrectly from the grower.

I won't argue but I feel certain the tags were correct- just being taken off the nursery truck- if that was it then you can't believe anything! At any rate, my new plants are in the ground-

We bought plants of Habanero peppers last year. A whole flat as non of ours germinated. They weren't even close to being Habanero. These came from the "Best" garden center in town.
Like they say money don't buy everything.

OK, I surrender-

Another thought. I think sulfur is what makes onions hot. If I remember correctly, the low sulfur content in GA soils is what makes Vidalias a big deal. Did you add sulfur to the soil?

If I'm wong about this, please let me know.

No, Willy- I don't add much of anything other than organics like compost, chicken manure, coffee grounds, etc. I had heard that a long time ago- isn't sulfur acidic? If so our soil here is pretty alkaline, so that shouldn't be it, but I give up worrying about it- they are planted and time will tell--

sulfur is very acidifying...great for growing bluberries.

hopefully you will have better luck this year...if not, the road side stands of Wall Walla, WA are a short drive away for you...

The local Farmers markets have plenty, too, but it's so good to be able to say "I grew it" !

You can say “you can’t believe anything” again, JoParrot, and believe it. Over the years I’ve purchased and grown–some for the better–many plants which were mislabeled. It’s mostly a problem caused by disgruntled employees and poor communication, I think.

This, for example: I’m presently visiting with several people, but we are unable to read each’s body language, tone of voice, and other keys which are so important to clear meaning. It’s the Tower of Babel all over again.

Don’t fall off! I hope youunses understood that.

I bought a hale haven peach tree a few years back. It is a beautiful specimen and gives me loads of wonderful peaches....

But the variety isnt hale haven. In fact I dont have the slightest what variety it is.

And it had two tags on it placed on it from the nursery but they turned out to be incorrect.

Mistakes happen all the time.

Hopefully this year you get some good onions true to variety! Yes much better when you grow them on your own. When I lived over in Pasco off of Road 68 I grew some beautiful Walla Wallas every year. Here in the east they dont do as well. I tend to get neck rot.

Belatedly reading this post-
Sulphur is what makes onions hot, cause tears, AND keep in storage. So if you plant "mild" variety, it means it doesn't take up sulfur well - but it helps if your soil is low in sulfur. But mild onions are for fresh use, they don't keep. And storage onions start out very strong, but often mellow out in storage. A little. Eventually. Cooking helps. If you can manage to cut them up.