These are a wonderful plant to grow in the garde, they are esay, useful in so many dishes and really a bit of a waste to buy large bunches when you only need a few at a time.
Now in ther UK they are called Scallions, and sometimes bunching Onions, they are all the same. They are are also called salad onions although they are often cooked as well, wspecially in asian dishes.
A humus rich well dug free draining soil is best, and they do like some sun as well. You can grow them from seed and although the white ones such as Lisbon are the more common, you can get red ones as well, just to ad a bit of color.
The time to plant is in spring, although in warmer sub tropical areas winte rplanting is successful.