How to Regrow Green Onions From Scraps (Water & Soil)

Regrowing green onions is the single easiest piece of kitchen gardening there is, and it costs nothing. Every time you buy a bunch of scallions, you also buy the part that grows them back: the white root end you would normally throw away. Stand those rooted stubs in a glass of water on the windowsill and within a few days fresh green shoots push up from the centers, ready to snip again in a week or two. It is the perfect project for a small apartment, a first-time grower, or a curious kid, because it works on a sunny ledge with no soil, no pots, and no special skill. This guide covers both the quick water method and the longer-lasting soil method, plus how to keep a single bunch producing for weeks or even months.

What You Need to Get Started

The beauty of this project is how little it requires. You need a bunch of green onions (also called scallions or spring onions) with the roots still attached — most grocery-store bunches have them, often with a rubber band around the white ends. You also need a small glass, jar, or narrow drinking glass, a sunny windowsill, and clean water. That is it for the water method. If you plan to move them into soil later, have a small pot with drainage holes and some potting mix on hand. Tap water is fine for most homes, though if your water is heavily chlorinated you can let it sit out for an hour to off-gas before using it.

When you buy or use your green onions, do not cut off and discard the root end. Instead, when you are cooking, slice the bunch about 1 to 2 inches up from the roots and keep those white, rooted bottoms. The green tops go into your meal; the white bases go into your glass. Choose the firmest, healthiest-looking root ends with the most intact roots, since those will rebound fastest. Limp or mushy bases that have been sitting in the fridge for a week may still work but will be slower and more prone to rot.

The Water Method: Step by Step

This is the fastest, most satisfying way to start, and it is what most people picture when they think of regrowing scallions.

1. Trim and save the bases. Cut the green onions about 1 to 2 inches above the roots, keeping the white root end with its little tuft of roots intact.
2. Stand them up in a glass. Place the rooted ends upright in a small glass or jar, roots pointing down. Bundle several together so they hold each other vertical.
3. Add about an inch of water. Pour in just enough water to cover the roots and the very bottom of the white stalk — roughly 1 inch. Do not submerge the whole stalk, or it will rot.
4. Set it in bright light. Place the glass on a sunny windowsill that gets at least four to six hours of light a day. A south- or east-facing window is ideal.
5. Change the water daily. Refresh the water every one to two days. This is the most important step — stale water turns slimy and smelly and will rot the roots.
6. Watch them grow. Within two to three days you will see fresh green shoots rising from the centers. In about a week to ten days they will be tall enough to harvest.

Each time you want green onions, snip what you need from the tops with scissors and leave the white base sitting in its water to grow again. A single set of root ends will typically regrow several times in water before it starts to weaken.

The Soil Method for Longer Harvests

Water regrowth is quick, but the onions live off stored energy and gradually thin out, because plain water has almost no nutrients. For sturdier, longer-lasting plants, move them into soil. You can plant fresh root ends directly into a pot, or transplant water-started stubs once they have a flush of new roots and one or two harvests behind them.

Fill a small pot or window box that has drainage holes with ordinary potting mix. Poke holes and tuck each root end in so the white base is buried and the green tops sit just above the surface, spacing them about an inch apart. Water well and place the pot in a bright spot with several hours of sun. Keep the soil lightly and consistently moist but not soggy. In soil, the plants can draw on real nutrients, so they grow thicker, greener, and keep producing for months. A light feeding with diluted liquid fertilizer every few weeks keeps them vigorous. This is a natural gateway into other easy container crops — our Urban Gardening hub has more small-space ideas once you are hooked.

Water vs. Soil at a Glance

If you want the absolute quickest result with zero equipment, start in water — it is perfect for a windowsill and great for trying the project out. If you want a renewable supply that keeps producing for months and stays robust, soil is the better long-term home. Many people do both: start in water to get fast results and the fun of watching roots grow, then pot the survivors up into soil to keep them going. Either way, the harvesting principle is the same — cut the green, keep the white.

Light, Care, and Common Problems

Light drives the regrowth, so give your onions as much bright light as you can. Four to six hours of direct sun on a windowsill produces the best, greenest growth. In a dim spot they will still sprout, but the shoots come up pale, thin, and floppy as they stretch toward the light, a condition called etiolation. If you only have a dark kitchen, a small grow light a few inches above the glass solves the problem entirely.

The number-one problem with the water method is neglecting the water. If you skip changes, the water clouds, develops a slimy film, and starts to smell — and the roots will rot and turn the bases mushy. Changing the water every day or two prevents all of this. Rinse the roots gently when you refresh the water, and wash the glass occasionally to clear any buildup. If a base goes soft or slimy, pull it out so it does not spoil the others.

You will also notice that water-grown onions get progressively thinner and milder with each regrowth, since there is no soil to replenish nutrients. This is normal and is the main reason to move them to soil for the long haul. The flavor stays perfectly good for cooking; the stalks just slim down over successive cuttings. When a clump finally exhausts itself, simply start fresh with the next bunch you buy.

Harvesting and Keeping It Going

Harvest with scissors, snipping the green tops down to about an inch or two above the white base whenever you need scallions for cooking. Always leave the white portion and roots intact — that is the engine that drives regrowth. Cut what you need and let the rest keep growing. With daily water changes or a pot of soil and decent light, a single batch of root ends can supply your kitchen for weeks on end, and a soil-grown clump can keep going far longer.

To never run out, stagger your supply: every time you buy and trim a new bunch, add the fresh root ends to your windowsill rotation. You will always have some onions at full height and others rebounding, so there is a constant supply to snip. It is a tiny habit that turns kitchen scraps into a free, perpetual harvest. Once green onions click for you, the same regrow-from-scraps logic works for a surprising number of foods, and you can branch into other beginner-friendly container projects from our plant and herb growing guides to build out a genuinely productive little kitchen garden.