The talk about onions... I did some research earlier today after I was last on here. Turns out zone 5 is ideal for the "day-neutral" varieties based on what I read. The short day is for southern climate who's says don't really lengthen much in the summer compared to winter. The long day are meant for zones 4 and below where days get particularly longer in the summer. Zone 5 and 6 definitely see fluctuations in day light, but we don't have long days (14 hrs) for a long enough time to grow long day varieties and the short day varieties tend to be adapted to hotter climates than we have.