In our area and latitude, late January to early February is the ideal time to start sowing seeds indoors for onion transplants. There are several advantages to growing your own onion transplants ...
Alternatively you could grow your onions from baby bulbs known as 'sets' instead. Onion sets are produced by growing onions from seed very close together. The immature bulbs produced are not large ...
Planting onions from small bulbs or "sets" is not the best way to grow large onions for storage. Plants grown from sets often begin blooming in mid-summer and stubbornly refuse to stop.