Regrow Green Onions, Celery and Herbs From Kitchen Scraps

The root end of a bunch of green onions is still alive when it hits your cutting board. Put it in a glass of water instead of the trash and it will send up fresh green shoots. Celery bases, leek ends, a sprouting garlic clove and a sprig of basil can all do the same trick.

Let's set expectations up front: you're not going to grow a whole new head of celery on a windowsill. What you get is a few bonus rounds of greens from food you already bought, plus a cheerful little project. There's an optional upgrade box near the end, but a glass and a window are all you need.

Why it's worth a spot on the windowsill

Green onions and fresh herbs are the kinds of things you buy for one recipe and then watch wilt in the crisper. A jar on the counter means you can snip exactly what you need, when you need it, fresh. That's fewer half-used bunches going to waste, and fewer extra trips to the store for a garnish.

It also gets one more use out of scraps before they head to the compost.

The free way, step by step

Step 1: Green onions (the easiest win)

Green onions, also called scallions, are the best place to start because they almost always work. When you use a bunch, cut the white ends off with about an inch or two of stem attached, keeping the little roots intact.

1. Stand the root ends upright in a small glass or jar.
2. Add just enough water to cover the roots and the bottom of the white part. Don't drown the whole stem.
3. Set the glass on a bright windowsill.
4. Change the water every couple of days.

New green shoots usually show up quickly. Once they're tall enough to use, snip what you need with scissors and leave the base in the water. They'll regrow several times, though each round tends to be a bit thinner than the last. When they get weak and spindly, plant the bases in a pot of soil and they'll keep going longer.

Step 2: Celery

Cut off the bottom of a celery bunch, leaving a base a couple of inches tall. Set it cut side up in a shallow dish with enough water to cover the bottom. Keep it in a bright spot and change the water often.

Small leaves and thin stalks will start to grow from the center. They're great for flavoring soups, but you won't get thick, grocery-store stalks in a dish of water. If you want more, plant the base in soil with the new growth just above the surface.

Step 3: Romaine lettuce

Romaine works the same way as celery. Expect a handful of small, tender leaves for a sandwich, not a whole new head of lettuce.

Step 4: Leeks

Leeks behave a lot like big green onions. Keep the root end with an inch or two of the white stem, stand it in a glass of water, and change the water every couple of days. New green growth will come up from the center. Snip it for cooking the same way you'd use green onions.

Step 5: Garlic greens

If a garlic clove has started to sprout a green shoot, don't toss it. Set the clove in a small glass with water touching just the bottom, or push it pointy end up into a pot of soil. The shoots are garlic greens, which taste like mild, fresh garlic and are great chopped over eggs or potatoes. Don't count on a new bulb this way; the greens are the goal.

Step 6: Herbs from cuttings

Basil and mint are two of the easiest herbs to root in water. Take a healthy sprig from a store-bought bunch or a friend's plant:

1. Cut a stem a few inches long, just below a spot where leaves grow (called a node).
2. Pull off the lower leaves so none sit underwater.
3. Stand the cuttings in a glass of water on a bright windowsill.
4. Change the water every couple of days.
5. When the roots are a couple of inches long, plant each cutting in a small pot of soil.

Once potted, pinch off the top leaves regularly and the plant will grow bushier instead of tall and leggy.

Water vs. soil: when to make the switch

Water is the fastest, easiest way to start, and it's fun to watch the roots grow. But water-regrown scraps give diminishing returns. After a few rounds, the growth gets thinner and slower, because the scrap is running out of stored energy and the water doesn't hold nutrients the way soil does.

When that happens, move the scrap to a pot of soil. Any container with a drainage hole works, including a yogurt cup with a few holes poked in the bottom. Plant it so the roots are covered and the new growth sits above the surface. Keep the soil lightly moist and the pot in a bright spot. Planted green onions and herbs can keep producing for much longer.

If you get hooked and want to grow food more seriously, our sister site Greenhouse Guide is a good next stop.

Common mistakes

• Too much water. Submerging the whole scrap invites rot. Keep the water to the roots and base.
• Letting the water sit. Stale water gets cloudy, slimy and smelly. Change it every couple of days.
• Too little light. A dim corner gives pale, floppy growth. Pick your brightest window.
• Expecting a full harvest. You're getting bonus greens, not a replacement for the store.

A good project for kids and small spaces

Scrap regrowing needs no yard, no tools and almost no space, which makes it a perfect apartment project. Kids love seeing the progress and snipping their own green onions for dinner. When the scraps are done, they go to the compost. Our guide to composting in an apartment can take it from there.

When the upgrade is worth it (and when it isn't)

A countertop hydroponic garden with a grow light is worth it if you don't have a bright window, or if you want fresh herbs through the winter. It handles light and water for you. A windowsill planter set is a cheap, tidy step up once you've moved scraps into soil and want matching pots with drainage trays.

If you're happy with a few glasses on the windowsill, you don't need either. The glass-and-water method is the whole point.