Onion long day short day?

Is there anyway to know if an onion variety is long day or short day iF it doesn't say on the package? Do the days to harvest help indicate which it is?
Excited to get onion seeds started I bought to packets from two big box stores and didn't bother to check the packs cause why would they sell short day varieties in the north right?  I looked them up online and one is in fact a short day so I mailed it of to a friend. The other name doesn't exist anywhere except the big box store website. I don't want to waste seed starting space on an onion that won't bulb.
Burped onion countrywide hybrid 125 days to harvest Spanish type.
Should I chance it, find new seeds or is there away to know.

I believe you can grow short day onions in a long day environment, they'll just be ready to harvest sooner. Long day varieties grown in a short day environment is a different story, and they may not fully mature under those conditions. It will still yield onions, just maybe not as large as they could be.

Days to harvest is a semi accurate method to tell if they are short day or long day. Another is to check the packet for best growing zone, most onion seeds that will grow in zone 3, 4 or 5 are going to be short day varieties.

The faster they mature to harvest, the shorter day type they are, unless you are talking about scallion producing varieties (those will be long day species).

Redhawk

James Freyr wrote:I believe you can grow short day onions in a long day environment, they'll just be ready to harvest sooner..

That would be good, I guess I'll plant them and see what happens.

Bryant RedHawk wrote: Another is to check the packet for best growing zone, most onion seeds that will grow in zone 3, 4 or 5 are going to be short day varieties. .

Redhawk

Oddly enough this packet and the one I mailed of both only show the color coded us map with outdoor sowing dates for the whole country.
I'm still confused that this variety name only exists at Walmart how it makes sense to have a specific variety and package just for them..? Strange.

Those are made up by Burpee for Walmart, it's a chain store thing, just like Kroger brand canned vegetables and even butter.