Ever thrown away the bottom of an onion without thinking twice? Well, next time, don’t! You can actually grow a whole new onion from that little leftover piece, and it’s a great way to teach kids how food grows. No fancy gardening skills required—just a little patience and a sunny spot will show them all they need to know to grow an onion.
Why Try This?
Growing an onion from scraps is a fun way to show kids that food doesn’t just come from the grocery store. It’s also a simple way to cut down on waste and learn a little about nature. Plus, watching those little roots grow is oddly satisfying!
What You’ll Need
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An onion bottom (the part with the roots still attached)
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A small cup or bowl
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Water
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A sunny windowsill
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Potting soil (if you want to plant it later)
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A small pot or garden space (optional)
Step-by-Step: How to Grow an Onion from Scraps
1. Save the Onion Bottom
Next time you chop an onion, keep the root end. You’ll want to leave about an inch of onion attached to it.
2. Put It in Water
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Fill a small bowl or cup with just enough water to cover the bottom.
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Place the onion root-side down in the water.
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Find a sunny windowsill and set the bowl there.
3. Wait and Watch
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In a few days, you’ll start seeing little white roots growing from the bottom and green shoots coming out of the top.
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Change the water every couple of days so it doesn’t get slimy.
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Let the onion grow in water until the roots look strong—usually about a week.
4. Time to Plant (Optional)
If you want to keep the onion growing, you can move it to soil.
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Fill a pot or small patch of garden space with good, loose soil.
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Dig a small hole and plant the onion root-side down, with the green shoots sticking out.
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Water it regularly and make sure it gets plenty of sun.
5. Keep It Growing
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Water the onion when the soil feels dry, but don’t overdo it.
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Onions love sunlight, so keep the pot in a bright spot.
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Over time, it’ll keep growing, and you might even get new onion bulbs forming.
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If you don’t want to wait for a full onion, you can trim the green shoots and use them like green onions in your cooking.
What Kids Will Learn
🌱 Where Food Comes From – Kids get to see firsthand how something as simple as an onion grows.
♻️ Less Food Waste – Instead of tossing scraps, they learn to reuse them in a cool way.
⏳ Patience & Responsibility – Taking care of a plant teaches kids how things grow over time.
🥗 Healthy Eating – Growing food makes kids more excited to eat fresh veggies!
Give It a Try!
This is one of the easiest (and cheapest!) ways to start growing food at home, and kids love seeing their onion sprout. Plus, it’s fun to check on its progress every day. So, next time you’re chopping an onion, don’t throw the bottom away—turn it into a mini science experiment!
For a growing method in soil, see Activity 4 in the Onion Ninja Activity Book, page 10.
