grow · Grow

How to Grow Green Onions in Water

Cut green onions about an inch above the white root end, place the root portions in a glass with water covering just the roots, and set on a sunny windowsill. New green shoots will appear in 3-5 days and can be harvested continuously for weeks.

Difficulty: Easy

Ingredients

1 fresh green onions with intact white root ends
water water

Step by step

Prepare the green onions. Use fresh green onions with intact white root ends. Cut them about 1 inch above where the white meets the green, saving the green tops for cooking. You want root pieces that are 2-3 inches long with visible root threads at the bottom.
Set up the growing container. Choose a clear glass or jar wide enough that the onion pieces won't crowd each other. Fill with enough water to cover just the white root portions - about 1 inch deep. The cut green ends should stay above water to prevent rot.
Position for growth. Place the container on a sunny windowsill or anywhere with bright, indirect light. Direct harsh sunlight can heat the water too much, but they need good light to grow strong green shoots.
Change the water regularly. Replace the water every 2-3 days or when it starts looking cloudy. Rinse the root ends gently under cool water before putting them back. Fresh water prevents bacterial growth and keeps the roots healthy.
Harvest the new growth. New green shoots will appear in 3-5 days. Once they reach 4-6 inches tall, cut what you need with scissors, leaving about an inch above the white part. They'll continue growing for several more harvests.

Tips & troubleshooting

Choose green onions with the thickest, firmest white portions - these have the strongest root systems
If roots start looking slimy or brown, trim them back to healthy white parts and change the water immediately
Room temperature water works better than cold water from the tap
After 3-4 harvests, the plants will weaken - start fresh with new store-bought green onions

Variations

Soil transplant method. After 1-2 weeks in water, transplant the rooted green onions into potting soil for longer-term growing and stronger plants that can produce for months.
Multiple container setup. Stagger plantings in several containers a week apart to ensure a continuous supply of fresh green onions without overwhelming yourself with too many at once.

Questions

How long will green onions keep growing in water?: They'll produce new growth for 3-4 weeks with regular harvesting and water changes. After that, the white bulb portions start to weaken and produce thinner, less flavorful shoots.
Can I use any part of store-bought green onions?: You need the white root end with visible root threads. If the roots have been trimmed completely off at the store, they won't regrow. Look for bunches with intact root systems.
Why are my green onions turning yellow or slimy?: Usually too much water covering the green parts, not enough light, or water that needs changing. Keep water level low, ensure good drainage, and change water every 2-3 days.
Do water-grown green onions taste the same as soil-grown?: The first few harvests taste nearly identical to store-bought. Later harvests may be slightly milder in flavor but are still perfectly good for cooking and garnishing.