Scallions - In as little as 5 days you can completely regrow a full scallion (or green onion) from the scraps. Leave about an inch attached to the roots and place them in a small glass with a little water. In a few days, you’ll have all new scallions.
Hydroponic Vegetables: Don't throw away your scraps. Regrow your veggies. It really works! Cut the bulb off a green onion and the bottom of a celery. Place in a little water (I use distilled), and place in a sunny window. Soon you will see roots and shoots grow from the green onion and celery stalk in the center of your celery bottom.
Carrot Greens - The ends of carrots you usually chop off and throw away will grow carrot greens if you put them in a dish with a little water. Set the dish in a well-lit windowsill and you’ll have carrot tops to use as a garnish or in salads.