Household weblog Homemade Serenity shares how scallion ends can regrow in in a glass of water. Just put the root ends in a glass of water and put that glass in a sunny window. After a few days you should be able to begin harvesting the green ends of the scallions. Make sure you change the water every so often and cut what you need with scissors before cooking.
You can see in the next picture how the roots grow and tangle in the cup of water. If you want to do this at home, it's simple. The next time you have green onions, don't throw away the white ends. Simply submerge them in a glass of water and place them in a sunny window. Your onions will begin to grow almost immediately and can be harvested almost indefinitely. We just use kitchen scissors to cut what we need for meals. I periodically empty out the water, rinse the roots off and give them fresh water.
Homeade Serenity via: Lifehacker
