Growing Green Onions in Water: A Simple, Rewarding Way to Keep Fresh Scallions on Hand
If you love fresh green onions as much as I do, you’ll adore regrowing them in water. It’s one of those small gardening wins that feels magical: a bunch of scallions goes from the grocery bag to a sunny windowsill, and within days you have bright, crunchy greens for your meals. I’ve been regrowing green onions this way for years—simple jars by the sink, constant little harvests—and I’m excited to share everything I’ve learned.
Why grow green onions in water?
There are lots of reasons to try this. It’s fast, space-saving, beginner-friendly, and almost foolproof. You don’t need soil, pots, or a big garden. Plus, it’s sustainable: instead of tossing the white root ends, you can regrow them into fresh scallions in under two weeks.
“There’s a special satisfaction in snipping fresh green onion tops from a jar on the windowsill—no store run required.”
What you’ll need
- Green onions/scallions with roots or the white bulb ends
- Clear jar, glass, or small vase
- Fresh water
- Sunny windowsill or a bright spot
- Optional: liquid fertilizer and a tray to catch drips
That’s it. I keep several jars on my kitchen sill year-round. They’re decorative, useful, and I love watching the roots grow.
How to regrow green onions step-by-step
Choose the right scallions
Buy a bunch from the store or use leftovers. Look for firm white bulbs with some roots or at least a fibrous base. If the roots were trimmed, they’ll regrow fine as long as the bulb isn’t mushy.
Prepare the bulbs
Trim the tops, leaving about 1–2 inches of green if you like, and keep the white base with roots attached. If you’re starting with grocery scallions, slice off the top (use it in soup), and place the bottom halves in a jar with the cut side up.
Place in water
Fill a jar so the roots are just covered. I change water weekly and keep it about 1–2 inches deep. Don’t submerge the entire bulb—just the roots. Too much water stresses the plant and invites rot.
Light and location
Place the jar in bright indirect light. A south- or west-facing window works well. If light is limited, a small LED grow light for a few hours each day will help. In my apartment I get great results on a bright kitchen sill.
Watch the roots and tops grow
Within a few days you’ll see roots lengthen and green shoots push upward. In about 7–14 days you should have ready-to-harvest green tops. The growth rate depends on light, temperature, and how often you change the water.
Harvesting and continual regrowth
Snip what you need with scissors about 1 inch above the bulb. The plant will regrow multiple times from the same base. When growth slows after a few regrowths, you can transplant to soil or start a new batch.
Tips for success and troubleshooting
Water quality and changes
Tap water is fine in most cases, but let chlorinated water sit out for a few hours if you’re picky. Change the water every 4–7 days to prevent algae and odor. If the water gets cloudy, change it immediately.
Preventing rot
If the white bulb becomes soft or smells bad, it’s likely rotting. Keep bulbs above the water line and only roots submerged. Trim any dark, slimy roots away and replace the water.
Nutrient boost
Green onions in water will eventually need nutrients for continued vigor. Add a diluted liquid fertilizer every 2–3 weeks (I use a quarter-strength balanced fertilizer) or transplant into potting mix for long-term growth.
When to transplant into soil
If you want larger bulbs or a longer lifespan, transplant into a pot with loose potting soil after you have a good root system. Plant the bulb so the soil covers the roots but not the entire stem. Keep evenly moist until established.
Common problems
- Yellowing tops — usually too little light or overwatering.
- Slow growth — insufficient light or nutrients.
- Mushy bulbs — rot from too much water or stagnant water.
Varieties and what to expect
Most scallions regrow easily, including common grocery green onions and spring onions. Bunching onions and Welsh onions also do well. Expect the tops to be tender and less bulbous than soil-grown onions, which is fine because you’re harvesting the greens.
Using your water-grown green onions
Fresh-cut tops are perfect for salads, soups, baked potatoes, omelets, stir-fries, and garnishes. I keep jars by the stove and snip off a little as I cook. It’s like having a mini herb garden right in the kitchen.
Personal note
I once forgot a jar of scallions on the sill for weeks; when I came back, the roots had taken over the glass. I ended up using them for a big batch of scallion pancakes. It was one of those small, homey victories that keeps me regrowing more.
Final thoughts
Growing green onions in water is one of the easiest, most rewarding ways to keep fresh greens at hand. It requires minimal tools, is kid-friendly, and looks pretty on a windowsill. Start a few jars this weekend—plant a jar on each sill—and you’ll be amazed how quickly a small habit turns into a steady supply of fresh flavor.
Happy regrowing! If you try it, I’d love to hear which jars are thriving on your windowsill.
