How to Re-Grow Onions From Onions at Home?
Regrow fresh onions from kitchen scraps instead of throwing them away. Two simple methods, water or soil, work for green onions and sprouted bulb onions. This step-by-step guide makes it easy. #RegrowOnions #KitchenScrapGardening #GrowFoodFromScraps #ZeroWasteCooking #IndoorGardeningTips
I still remember the day I almost threw away an onion that had started sprouting in my pantry. I thought it was trash. But then a friend told me, “You can grow that.” I was skeptical. But I tried it anyway. And guess what? It worked.
Now I never throw away onion scraps. I grow fresh green onions on my windowsill all winter long. I have saved so much money and reduced so much food waste. Let me show you how you can do the same thing, even if you have never grown anything before in your life.
🌱 What You Can Regrow: Two Different Goals
First, you need to understand what you are actually going to grow. There are two different results, depending on what you start with and how much patience you have.
If you want a fast harvest, go with green onions. You will see new growth in just a few days. If you want to try for full-size onions, start with a sprouted bulb onion and be patient.
🧅 Method 1: Regrowing Green Onions (Fastest & Easiest)
Green onions are also called scallions or spring onions. They are the thin ones with long green tops. This method works amazingly well, and you will see results almost immediately.
What You Need
Step-by-Step in Water (The Windowsill Method)
This is the easiest way to start. I keep a little glass jar on my kitchen windowsill all the time now.
Step 1: When you cook with green onions, do not throw away the white ends. Cut them so you leave about 2 to 3 inches of the white part, with the little roots still attached at the very bottom.
Step 2: Take a small glass or jar. Place the root ends down into the glass. The roots should touch the bottom.
Step 3: Add just enough water to cover the roots. Do not submerge the whole white part. Only the bottom half-inch or so should be in water.
Step 4: Put the glass on a sunny windowsill. Onions need 4 to 6 hours of sunlight per day to grow well.
Step 5: Change the water every 2 to 3 days. This keeps the water clean and prevents bad smells and bacteria.
Step 6: Watch them grow! Within 24 to 48 hours, you will see tiny new green shoots coming out of the top. In about a week, the green tops will be several inches tall.
Step 7: Harvest by snipping off the green tops with scissors. Leave about 1 inch of green above the white part. The onion will keep growing back.
🥬 My Personal Experience: The first time I tried this, I checked my onions every few hours like a kid watching a pot of water boil. And then, on the second day, I saw tiny green tips popping up. I literally called my wife over to look. We were both amazed. Now I always have a jar of regrowing green onions on my windowsill. It never gets old.
How Long Will They Last in Water?
Growing green onions in water is very fast and easy, but the plants cannot live in water forever. They will eventually run out of energy and stop producing good shoots, usually after about 4 to 6 weeks or 3 to 4 harvests.
When the shoots start getting thin and pale, it is time to move them to soil.
Step-by-Step in Soil (Stronger & Longer-Lasting)
Soil is better than water for long-term growth. The roots get more oxygen, and the plant gets more nutrients.
Step 1: Prepare a small pot with drainage holes. Fill it with well-draining potting soil. Do not use garden soil; it is too heavy and can bring pests inside.
Step 2: Follow the same first steps as the water method. Save your green onion scraps with 2-3 inches of white and the roots attached.
Step 3: Dig a small hole in the soil and place the root end down. Bury the roots and the white part, but leave the very top of the cut bulb exposed above the soil.
Step 4: Water the soil lightly so it is damp but not soaking wet.
Step 5: Place the pot on a sunny windowsill. Keep the soil moist, but do not overwater. Water about once a week or when the top inch of soil feels dry.
Step 6: Harvest the green shoots by snipping them close to the soil level. The base will keep producing new shoots many times.
🧄 Method 2: Regrowing Sprouted Bulb Onions (Yellow, Red, White)
Sometimes you find an onion in your pantry that has started to sprout. The green shoots are coming out of the top, and the onion looks old. Do not throw it away! This is actually a perfect opportunity to grow new onions.
Step-by-Step: From Sprouted Onion to New Plants
Step 1: Look at your sprouted onion. There is usually more than one sprout growing from the top. Each sprout can become its own new onion plant.
Step 2: Gently peel away the papery outer layers of the onion. Keep peeling until you can see where each green sprout connects to the roots at the bottom.
Step 3: Carefully separate the onion into sections. Each section should have one green sprout and part of the root plate (the flat bottom where the roots grow).
Step 4: Fill a pot with well-draining potting soil. Make sure the pot has drainage holes.
Step 5: Plant each sprout section into the soil. Bury the root end, and leave the green shoot pointing up. Plant them about 1 inch deep.
Step 6: If you are planting multiple sprouts in one pot, space them about 4 inches apart so they have room to grow.
Step 7: Water the soil lightly and put the pot in a sunny spot. Onions need at least 6 hours of sunlight per day.
Step 8: Water when the top inch of soil feels dry. Do not let the soil get soggy.
Step 9: In about 2-3 months, you may see small new onion bulbs forming. They will not be as big as store-bought onions, but they will be edible and tasty. In about 90 to 120 days, you can harvest a full onion bulb.
🧅 My Personal Experience: I once had an old red onion that had been sitting in my pantry for weeks. It had three big green shoots coming out of it. I separated it into three pieces and planted each one in its own small pot. Two of them grew into nice little onions. The third one only grew green shoots, but I used those shoots like chives in my cooking. It was like getting free food from something I was about to throw away.
📋 Quick Reference: Water vs. Soil
Here is a simple side-by-side comparison to help you decide which method to use.
| Feature | Water Method | Soil Method |
|---|---|---|
| Setup time | 2 minutes | 5 minutes |
| Materials needed | Glass jar, water | Pot, potting soil |
| See first growth | 1-2 days | 3-7 days |
| How long it lasts | 4-6 weeks (3-4 harvests) | Several months (many harvests) |
| Best for | Quick harvest, kids’ project | Long-term supply, stronger plants |
| Can you grow full bulbs? | No | Possibly, with patience |
❌ Common Mistakes (And How to Avoid Them)
I have made every mistake on this list. Learn from me so you do not have to make the same errors.
✨ Tips for Maximum Success
Here are the little tricks I have learned that make a big difference.
Use Clean, Sharp Scissors for Harvesting
When you cut the green shoots, use clean scissors. Make a clean, straight cut. Jagged cuts from dull blades can invite bacteria and slow down regrowth.
Do Not Cut Too Low
When harvesting from water, leave about 1 inch of green above the white part. The plant needs some leaves to keep photosynthesizing and growing back.
Rinse Before Planting
Give your onion scraps a gentle rinse under cool running water before you put them in water or soil. This washes away any dirt or bacteria that could cause rot.
Let the Cut Surface Dry
If you cut a fresh onion bottom, let it sit out on a paper towel for about 30 minutes before putting it in water. This allows a slight callus to form, which helps prevent rot.
Use Filtered Water if Possible
If your tap water has a lot of chlorine or other chemicals, use filtered water instead. This is especially important for the water method.
Transplant from Water to Soil for Stronger Plants
Green onions grown only in water will eventually get weak and stop producing. When you see the shoots getting thin and pale, transplant them into a pot with soil. They will bounce back and grow much stronger.
🌿 How Many Times Can You Regrow?
This is a question I get asked a lot. Here is the honest answer.
| Method | How Many Harvests? | Why It Stops |
|---|---|---|
| Water method | 3 to 5 harvests | The plant runs out of stored energy in the bulb |
| Soil method | 10+ harvests, sometimes indefinitely | The plant can grow new roots and get nutrients from soil |
Green onions grown in water will eventually stop producing because they are living off the energy stored in the white bulb. After a few harvests, that stored energy runs out. But the same plant moved to soil can keep growing for a long time.
🏠 What to Do With All Those Green Onions
Once your green onions start growing, you will have more than you know what to do with. Here are my favorite ways to use them.
- Snip fresh over soups and stews. Just before serving, cut a few green shoots over the bowl.
- Mix into scrambled eggs. The mild onion flavor is perfect with eggs.
- Add to stir-fries. Cut them into 1-inch pieces and toss in at the very end.
- Use as a garnish for baked potatoes. A sprinkle of fresh green onion makes any potato better.
- Make green onion pancakes. A classic Korean dish that is delicious.
- Add to salad dressing. Chop finely and mix into vinaigrette.
📋 My Weekly Green Onion Maintenance Routine
This is what I actually do in my own kitchen. You can copy me.
Every day:
- Look at my water jar. Does the water look cloudy? If yes, change it.
Every 2-3 days:
- Change the water in my water jar. Rinse the roots gently.
- Check the soil in my potted onions. If the top inch is dry, water lightly.
Every week:
- Harvest any green shoots that are 4-6 inches tall.
- Rotate my pots so all sides get even sunlight.
- Wipe down the windowsill to keep it clean.
Every few weeks:
- If my water-grown onions look tired, I transplant them into soil.
- I start new scraps from the next batch of green onions I buy.
❓ People Also Ask
Can I use any onion from the grocery store?
Yes. Most onions from the grocery store will regrow, as long as they are fresh and healthy. Organic onions sometimes regrow better because they have not been sprayed with growth inhibitors.
How long until I see new growth?
In water, you will often see tiny new green shoots within 24 to 48 hours. In soil, it takes a little longer, usually 3 to 7 days.
Why are my onion shoots turning yellow?
Yellow shoots usually mean one of two things: not enough light, or the plant is running out of energy. Move it to a sunnier spot. If that does not help, transplant it into fresh soil.
Can I grow full-sized onions from scraps?
Yes, but you need patience. Full-sized bulb onions take 90 to 120 days to grow from a sprouted bottom or sprouted onion piece. You also need good soil, lots of sun, and consistent watering. The green shoots come much faster.
What do I do if my water starts to smell?
Change the water immediately. Rinse the roots gently under running water to wash away any slime. If the roots themselves look brown and mushy, start over with fresh scraps.
🏁 The Bottom Line
Regrowing onions at home is one of the simplest and most satisfying gardening projects you can do. It costs almost nothing. It takes almost no space. And it gives you fresh food from scraps you would have thrown away.
Start with a glass of water and some green onion bottoms on your windowsill. You will see new growth in just a day or two. Once you see that first tiny green shoot pushing up, you will be hooked. I know I was.
Your kitchen scraps are not trash. They are the start of your next harvest.
