“Don’t They Get Slimy?” 6 Green Onion Regrow Myths, Cleared Up

Regrowing green onions in a glass of water is the easiest grow there is, which is exactly why people don’t believe it works — or believe it works worse than it does. Here are the six things beginners get wrong about the free windowsill scallion.

Myth 1: “It won’t actually regrow — that’s an internet trick”

It genuinely works, and fast. Stand the trimmed white root-ends in an inch of water on a windowsill and the green tops start visibly regrowing within a day or two, giving you a usable second harvest in about a week. The plant still has its roots and stored energy; you’re just giving it water and light. This is the most reliable grow in the entire series.

Myth 2: “If it gets slimy, the whole thing has failed”

Slime and a sour smell are the one common problem — and they have a single cause: old water. The fix is the one rule that prevents nearly every issue: change the water daily (or close to it), and give the glass and roots a quick rinse. Keep the water fresh and the roots stay firm and white. It’s two minutes a week of attention, total.

Myth 3: “Regrown onions have no nutrition left”

They’re still a real allium. The regrown green tops carry the same family of organosulfur compounds, quercetin, vitamin K, and vitamin C that make scallions worth eating — the plant is actively growing new tissue, not running on empty. You’re regrowing food, not a decoration. (For the full research picture, see the companion health post.)

Myth 4: “You can regrow them forever in the glass”

Honest answer: no. In plain water you’ll typically get 2–3 good regrows before the bulb runs low on stored energy and the new growth gets thin and pale. That’s normal — water has no nutrients to replace what the plant uses. The upgrade is simple: move tired bulbs into a small pot of soil and they’ll keep producing for months instead of weeks.

Myth 5: “It only works for green onions”

The same trick works on romaine lettuce bases, celery hearts, and leeks — any plant that regrows from an intact root or stem base. Green onions are just the fastest and most reliable, which is why they’re the place to start. Once you’ve seen one glass work, you start eyeing every root end before it hits the bin.

Myth 6: “There’s no point — they’re cheap anyway”

True, scallions are inexpensive. But the point was never to save a fortune; it’s the zero-cost proof that growing your own food works. A glass by the sink, a week of watching green tops climb, and the habit either clicks or it doesn’t — for free, before you ever buy a thing. It’s the lowest-risk way to find out if home growing is for you.

Key takeaway: Regrowing scallions in water genuinely works; slime just means change the water daily. The regrown tops are still a nutritious allium, you’ll get 2–3 regrows in water (more in soil), and the same trick works on romaine, celery, and leeks. It’s a free test of the whole habit.