Approved Guide
How to Grow Onions in Water for Fresh Green Scallions
Growing onions in water is a rewarding and sustainable way to turn kitchen scraps into a continuous supply of fresh green onions. This hydroponic approach allows you to observe the root system develop in real-time, making it an excellent educational project for children or a low-maintenance addition to a city apartment. While you won't grow a full bulb in a glass, you can harvest delicious green shoots for your cooking.
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1
Poke four toothpicks, equally spaced, around the circumference of an onion.
For the onion to sit above the water without falling in, you will need to make sure the vegetable is supported. Make sure the toothpicks are placed just slightly below the middle of the onion.
- For the onion to sit above the water without falling in, you will need to make sure the vegetable is supported.
- Make sure the toothpicks are placed just slightly below the middle of the onion.
- For the onion to sit above the water without falling in, you will need to make sure the vegetable is supported.
- Make sure the toothpicks are placed just slightly below the middle of the onion.
- For the onion to sit above the water without falling in, you will need to make sure the vegetable is supported.
2
Set the onion, roots down, on top of the glass with the toothpicks resting on the rim.
The roots and base of the onion should be immersed in water. This way, the roots will be able to take in water and allow the onion to grow while the rest of the onion is surrounded by air and not rot.
- The roots and base of the onion should be immersed in water.
- This way, the roots will be able to take in water and allow the onion to grow while the rest of the onion is surrounded by air and not rot.
- The roots and base of the onion should be immersed in water.
- This way, the roots will be able to take in water and allow the onion to grow while the rest of the onion is surrounded by air and not rot.
- The roots and base of the onion should be immersed in water.
3
Place the glass with the onion onto a windowsill that gets plenty of sunlight.
Onions need at least six hours of sunlight to grow well. You also want to make sure you don't forget about the onion, so find a nice sunny windowsill that is in a busy part of your home. Now, all that’s left is to wait and watch your onion grow. Over a week, you will see the roots grow into the water, and a green sprout will rise from the top.
- Onions need at least six hours of sunlight to grow well.
- You also want to make sure you don't forget about the onion, so find a nice sunny windowsill that is in a busy part of your home.
- Now, all that’s left is to wait and watch your onion grow.
- Over a week, you will see the roots grow into the water, and a green sprout will rise from the top.
- Onions need at least six hours of sunlight to grow well.
4
Plant the onion in the soil when you notice a flower stem emerging from the top.
Growing an onion in water is a really fun way to watch the early steps of vegetable growth. However, the onion cannot grow this way forever. After a few weeks, a flower stem will emerge. At this point, you can either plant the entire onion in the soil or just discard the onion. After the onion has started to flower, it can no longer grow in water and must be potted in soil.
- Growing an onion in water is a really fun way to watch the early steps of vegetable growth.
- However, the onion cannot grow this way forever.
- After a few weeks, a flower stem will emerge.
- At this point, you can either plant the entire onion in the soil or just discard the onion.
- After the onion has started to flower, it can no longer grow in water and must be potted in soil.
5
Slice whole green onions where the white stalk meets the green leaf.
Perhaps you already have a pile of cut green onions that you were going to throw away. If so, great! Just use those. If not, grab a fresh bunch of green onions (also known as scallions or spring onions) and carefully use a knife or scissors to make the proper cut.
- Perhaps you already have a pile of cut green onions that you were going to throw away.
- If so, great!
- Just use those.
- If not, grab a fresh bunch of green onions (also known as scallions or spring onions) and carefully use a knife or scissors to make the proper cut.
- Perhaps you already have a pile of cut green onions that you were going to throw away.
6
Place the green onion scraps root down into a clear glass.
Find a glass or jar that is relatively narrow, so that the green onion scraps will be supported and held up vertically. These will be growing on your windowsill for a while, so you may want to use a decorative glass or a vase that will look nice in your kitchen.
- Find a glass or jar that is relatively narrow, so that the green onion scraps will be supported and held up vertically.
- These will be growing on your windowsill for a while, so you may want to use a decorative glass or a vase that will look nice in your kitchen.
- Find a glass or jar that is relatively narrow, so that the green onion scraps will be supported and held up vertically.
- These will be growing on your windowsill for a while, so you may want to use a decorative glass or a vase that will look nice in your kitchen.
- Find a glass or jar that is relatively narrow, so that the green onion scraps will be supported and held up vertically.
7
Add enough water to cover the roots of the green onion stalks.
You want the roots to be completely immersed in water, but pouring water a little higher up will make sure the green onions don’t use up all the water before you have time to refill it.
- You want the roots to be completely immersed in water, but pouring water a little higher up will make sure the green onions don’t use up all the water before you have time to refill it.
- You want the roots to be completely immersed in water, but pouring water a little higher up will make sure the green onions don’t use up all the water before you have time to refill it.
- You want the roots to be completely immersed in water, but pouring water a little higher up will make sure the green onions don’t use up all the water before you have time to refill it.
- You want the roots to be completely immersed in water, but pouring water a little higher up will make sure the green onions don’t use up all the water before you have time to refill it.
- You want the roots to be completely immersed in water, but pouring water a little higher up will make sure the green onions don’t use up all the water before you have time to refill it.
8
Place the glass filled with green onions on a sunny windowsill.
Now, all you need for your green onions to grow is sunlight and time.
- Now, all you need for your green onions to grow is sunlight and time.
- Now, all you need for your green onions to grow is sunlight and time.
- Now, all you need for your green onions to grow is sunlight and time.
- Now, all you need for your green onions to grow is sunlight and time.
- Now, all you need for your green onions to grow is sunlight and time.
9
Cut the green sprigs off the stalk or plant the entire bulb in soil.
The green onions will only grow so tall. Once the green stalk is 8 inches (20 cm) or more, you can either cut off the green stalk and use the green onion as an ingredient, or you can plant the entire thing in soil (roots, white bulb, and green stalk) and continue to watch it grow.
- The green onions will only grow so tall.
- Once the green stalk is 8 inches (20 cm) or more, you can either cut off the green stalk and use the green onion as an ingredient, or you can plant the entire thing in soil (roots, white bulb, and green stalk) and continue to watch it grow.
- The green onions will only grow so tall.
- Once the green stalk is 8 inches (20 cm) or more, you can either cut off the green stalk and use the green onion as an ingredient, or you can plant the entire thing in soil (roots, white bulb, and green stalk) and continue to watch it grow.
- The green onions will only grow so tall.
Pro Tips
- To speed up growth, you can add a tiny drop of liquid hydroponic fertilizer to the water once a week.
- Experiment with different onion colors to see which variety grows the fastest in your environment.
Warnings
- Be vigilant about 'damping off' or root rot; if the roots turn brown and mushy, discard the onion and start over.
- Avoid using distilled water exclusively, as some minerals found in tap water can help the plant.
Community Q&A
Q Can I grow a full onion bulb in water?
A No, water provides enough hydration for the greens to grow, but the plant needs the minerals and nutrients found in soil to develop a full, edible bulb.
References
- https://www.rhs.org.uk/vegetables/onions/grow-your-own
- https://extension.umaine.edu/gardening/manual/propagation/
- https://extension.umn.edu/vegetables/growing-onions
- https://www.wifss.ucdavis.edu/wp-content/uploads/2016/10/GreenOnions_PDF.pdf
- https://verticalveg.org.uk/blog/91293-multiple-spring-onions-scallions-from-one-pot
- https://www.iowaspecialtycrop.org/planting-and-growing-onions/
- https://extension.sdstate.edu/onions-how-grow-it
- https://cceschoharie-otsego.org/gardening/food-gardening/guide-for-growing-garlic
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