So since my onions finally appear to be growing, I’m already thinking about next year. I’m researching a few varieties I’d like to try between storage capability and day-length adaptability.

My latitude is just a hair north of the 39th parallel, not far from Baltimore, MD, but a bit further inland (Howard County).

Some websites (Johnny’s Seeds, for one) actually go deeper than just “long day” or “short day” and give a latitude range. My question is, does the location have to be wall-to-wall full sunshine for the plant to “register” the day length? My yard has a decent amount of sunshine, but I’m surrounded by trees, so the sun doesn’t actually rise over the treeline until about an hour after sunrise, and goes below the treeline about an hour and a half before sunset.

To put it another way, how much light (intensitywose) triggers the day length response in an onion? Deep shade? Any light at all? Something nearer to full sun?

This year I’m growing Sierra Blanca and Candy, both intermediate-day varieties, but both appear to have lousy storage capability.

There are the varieties I want to try next year:

For flavor/size:

Ailsa Craig

Walla Walla

For storage:

Pontiac (almost all sources say it stores very well)

Expression (seems to have moderate storage ability, 3-4 mos or so)

Pontiac I mainly want for storage, but I wonder about flavor, since nothing really seems to say if it’s “mild,” “sweet” or “hot” or whatever. Any other suggestions or recommendations? My family and I mainly prefer white and yellow types, as opposed to red.