Question: what is the difference between short day and long day onions?
Answer: Long-day onions need about 14 to 15 hours of daylight to bulb. Short-day onions need 10 hours of daylight. Day-neutral onions form bulbs regardless of daylight hours and produce well in almost any region. ... Conversely, if you live where daylength never hits 14 hours, long-day onions will never form a bulb.