Onions, under proper conditions, are practically self-replicating. A cutting or portion of an onion or green onion can be used to grow more of the same, although the methods and portions used to regrow each vary slightly. Start your onion-regrowing project with an organic variety for healthiest results; this way you'll know no chemicals linger in the fresh onions you grow from scraps. Growing green onions from cuttings is an ideal way to get children interested in kitchen windowsill gardening projects because they can measure new growth each day or week.
Things You'll Need
- Green onions
- Kitchen knife
- Cutting board
- Shallow vase, glass or jelly jar
- Onion with visible roots
Scallions or Green Onions
Cut a bunch of green onions (Allium fistulosum), sometimes called scallions, approximately 2 inches from the root end of the plant with a kitchen knife on a cutting board. Set the greens aside for cooking.
Place the onions root-end down in a clean, shallow vase, glass or jelly jar. The cut green end should be sticking out of or near the top of the glass.
Add enough water to the glass to cover the onion roots. Place the glass in an area that receives ample sunlight, such as on a windowsill.
Replace the water every few days or when the water looks a bit cloudy.
Green onions or scallions take about two weeks to grow to near their original length; cut them back and start again to regenerate the green growth. It's the green part that regrows each time, rather than the white bulbous portion, so you'l be able to regrow the same onion multiple times.
Grow any larger onion variety -- the type in which the bulb is eaten rather than the greens -- from a small cutting of the bulb. Slice off the bottom of an onion with exposed roots, saving the rest of the onion for meals.
Bury the slice root-end down in a sunny location in soil just deep enough to cover the onion.
Water as needed to keep the soil around the onion moist. Harvest onions when the leaves begin to lose their color and wilt, which may be four to six months after planting. One root end of a bulb grows into a full bulb; the greens can be snipped and harvested earlier to use for cooking or salads.