Grow Fresh Onions at Home—No Soil Needed!

Imagine harvesting your own fresh green onions right from your windowsill—all without soil, mess, or expensive gardening supplies. Sounds too good to be true? Not at all. With just a few everyday items like egg cartons or plastic bottles, and a bit of care, you can grow flavorful green onion tops all winter long.

This simple, budget-friendly method is perfect for beginners, small spaces, or anyone who loves fresh herbs in their kitchen. Let’s walk you through how to get started, step-by-step.

Why Grow Onions Without Soil?

Onions, especially green onions (also known as scallions), don’t need a traditional garden bed to thrive. The part we typically use in cooking—the green stalks—can regrow multiple times from a single onion bulb with just water and light.

That means even if you don’t have a backyard or garden, you can still enjoy fresh, homegrown produce from your windowsill.

Method 1: Egg Carton Starter

This is one of the easiest ways to get started with regrowing onions:

What You’ll Need:

A cardboard or plastic egg carton

Several small onions (even slightly sprouted ones are perfect)

A tray or shallow container for water

Steps:

1. Place your egg carton on a tray to catch any excess water.
2. Put one onion in each egg cup, root side down.
3. Add just enough water to the tray to touch the bottom of the onions. The goal is to keep the roots moist without submerging the bulb.
4. Place the setup near a sunny window. Within a few days, you’ll see green shoots start to grow
5. .

Maintenance Tip: Every few days, check the water level and top it off as needed. Replace the water weekly to avoid odors or mold.

Method 2: Plastic Bottle Vertical Garden

Want to scale up your onion growing? Try the plastic bottle method—it’s great for maximizing space and growing more at once.

You’ll Need:

A clean plastic bottle (2L or more)

A knife or scissors

A few small onions

Water

How To Do It:

1. Cut holes around the bottle, spaced about 2 inches apart. Make sure they’re just big enough for an onion to poke through.
2. Fill the bottle with water, up to the base of the lowest holes.
3. Insert onions into the holes, root side in, so the green tops can grow outward.
4. Place the bottle in a sunny spot. Within days, green shoots will emerge from every onion.

Bonus: A single bottle can grow more than 40 onion shoots—enough to supply your kitchen for months!

When to Harvest

Once your green shoots are about 6 to 8 inches tall, they’re ready to be snipped. Use clean scissors to trim what you need, leaving at least an inch of stalk behind.

The best part? These onions will continue to regrow after each cut—up to three times or more! Just be sure to keep them hydrated and in a sunny spot.

Ideal Conditions for Regrowth

Sunlight: Place your growing setup near a window that gets at least 4–6 hours of sunlight daily. If your space is low on light, a small grow lamp can help.
Water: Keep the roots submerged, but don’t drown the bulb. Standing water can cause rot, so regular maintenance is key.
Temperature: Onions prefer cooler indoor temperatures, ideally between 15°C and 22°C (59°F to 72°F).

Best Onions to Use

Small onions that have started sprouting are ideal—they’re already in “growth mode.” You can use:

White onions

Yellow onions

Red onions

Even shallots or leftover scallion bases

The only ones to avoid are bulbs that are mushy or moldy.

Why You’ll Love This Method

Zero waste: Give old or sprouted onions a second life.

No soil or mess: Perfect for apartments and kitchens.

Saves money: Fresh green onions on demand—no trip to the store needed.

Fun and educational: Great for kids and adults alike to learn about plant growth.

Final Thoughts

Growing green onions in water is not only easy—it’s rewarding, too. Whether you choose the egg carton method for a simple start or build a vertical garden with plastic bottles, you’ll have fresh, flavorful greens at your fingertips in just a few days.