Bulbs are best for spring or green onions. The other thing is to get "day neutral" plants. Here in Mid-Missouri, we do not have excessively long or short days so day neutral onions do best here.

There are short-day onions, intermediate-day (or day-neutral onions), and long-day onions, with different varieties in each of the three categories.

Intermediate-day (day-neutral) onions grow best from 32-42° N and are triggered into bulbing when days are between 12-14 hours long. In cooler climates, they are usually planted in spring and ...

Comments: "There are very few day-length neutral onions. 'Super Star' tastes great and has disease tolerance to pink root, too. It is rare for an onion to be adaptable to as many growing ...

According to the Virginia Master Gardener Handbook, the best choice of onion to grow in Virginia is a day neutral, early maturing variety. Long day onions are a Northern variety and require 16 hour ...

High temperatures favour bulbing and curing. In the tropics, only short day or day neutral onion varieties will form bulbs. These thrive in warm to hot climates of 15 to 30 degrees Celsius.