Every year I plant 2 - 3 types. They take months to grow but I usually get a few small bunches. Plant in October (soil needs to cool off a bit for germination) and harvest in April.

In my garden, they are very good.

I've kept 3 pots of perennial onions growing for years now, They are Egyptian Walking onions and Welsh onions. You can cut the tops and some of the white base too, and they continue to grow back and multiply, along w/ occasionally topsetting little bulbils from the flowers.

1 is more pungent than the other, but I forgot which is which after all these years. I just keep adding compost and fertilizer, along w/ some alfalfa pellets (rabbit food), and they continue to provide us w/ lots of fresh green onions.

I got both from Pinetree Garden Seeds, but it looks like they don't carry them any more.

When i buy scallions i only eat the tops and plant the white part. Most grow and then i can just cut the tops off the green while they are still in the ground and they continue to grow tho eventually seem to peter out tho some have some babies. I grow them in pots. But i never seem to have enough for what i use.

I've been buying scallions in the grocery store, and I keep the bulbs in water by a window. They do grow that way, but eventually the bulb gets squishy. After reading the replies, I shall now try planting the bulbs in some decent soil and see what happens.