Last year a few small onions were left out on the soil to dry & I wasn’t really sure what to do with them, so I replanted them in spring to see what happened!
They all grew, and some split into two bulbs, but they all have bolted to produce tall flower spikes.
After onions bolt, the bulbs won’t get any bigger as the plant is concentrating on producing flowers, so the only options are to
1) pull them up and use what you can or
2) leave them to continue to flower and produce seeds for next year
I decided to do a bit of both & I’ll report back on whether the flowers go to seed later in the year.