How to grow a year's supply of green onions for under $1
Once you see roots, transplant the green onions into a pot or the garden. As you need green onions, simply cut off the leaves about an inch above the level of the dirt. The plants will regrow to full size in a little over a week.
One time I didn't need any green onions for about a month and let them grow, when I finally harvested the leaves they were two feet long and the bunch weighed almost a pound! No problem, I just chopped them up and froze them in a gallon sized ziplock bag.
Since I'm gardening in zone 9, the green onions live year round! They even bloom in the spring, and if you leave the buds on the plants, they will drop their seeds and start a new crop all on their own. Now you know that one bunch from the grocery store is more than enough for the whole family!