We planted sweet onions in the spring last year in raised beds. The onions didn’t grow much so we left them in all winter. This spring the tops of the onions grew 2 to 3 feet tall and bloomed. The onions are still small and now have sections that are tough and of the same consistency as the 2 foot trunk section through the center of the bulb. What are we doing wrong?
Onions are biennials, which means they bloom in their second season of growth. As with a lot of plants, they get woody and not very appetizing once they've flowered. It sounds like they just didn't have enough time to grow in their first season. Onions take a while, and should be started indoors before the last frost. Especially if you're growing them from seed, they should be planted 2 to 3 months before the last frost, then transplanted out when the weather warms up.
This article will tell you more about that: