Can You Replant Spring Onions?
Yes, you can replant spring onions, also called scallions or green onions. In fact, with just a few simple steps, you can turn the white bulbs from your kitchen into a new crop that keeps growing and giving you fresh greens for weeks. This guide answers the most common questions about replanting spring onions so you can enjoy a steady, low-cost supply right from your windowsill or garden.
How do you replant spring onions from store-bought ones?
The process is surprisingly easy. All you need is a bunch of spring onions from the grocery store (or your garden), a container or patch of soil, and water. Follow these steps:
- Cut back the green tops to about 2–3 inches above the white bulb. Use the trimmed greens in cooking.
- Remove any dry or slimy outer layers from the bulb. Keep the root end intact – the little brownish root hairs are essential.
- Place the bulbs in a glass or jar with enough water to cover the roots. The white part should sit just above the water line so the center doesn't rot.
- Set the jar in a bright spot (a sunny windowsill works well). Change the water every 2–3 days to keep it fresh.
- In about 3–5 days you will see new green shoots emerging from the top. At this point you can either keep them in water or move them to soil.
If you want to grow them in soil instead, simply plant the bulbs root-down about an inch deep, firm the soil around them, and water gently. Keep the soil moist but not soggy for best results.
Can you regrow spring onions in water only?
Yes, spring onions will regrow in water for several rounds. Many people keep a jar of them on the counter for constant access to fresh greens. However, water-only regrowth has limits. The bulbs will produce three to four flushes of green shoots, but each time the new leaves get thinner and less flavorful. For long-term success, move them to soil after the first or second regrow. Soil provides more nutrients, leading to thicker, tastier stalks. If you love the convenience of water, you can keep a small jar going and replace bulbs every few weeks with fresh ones.
How long does it take for spring onions to regrow after replanting?
In water, you’ll see new green tops in 3 to 7 days, depending on light and temperature. The fastest growth happens when the room is warm (around 65–75°F / 18–24°C) and the onions get at least 6 hours of bright, indirect sunlight daily. In soil, the first tender green shoots appear in about one week. You can start harvesting the green tops once they reach 6–8 inches tall, usually 2–3 weeks after planting. If you want larger bulbs and thicker white stems, leave them in soil for 4–6 weeks. Spring onions are not a “set it and forget it” crop – they need consistent moisture and light to keep growing.
What are the best conditions for replanting spring onions?
Spring onions are not fussy, but a few things help them thrive:
- Light: They need at least 6 hours of bright, indirect sunlight per day. A south-facing window is ideal. If natural light is weak, use a simple grow light.
- Temperature: Cool to moderate temps (60–75°F / 15–24°C) are perfect. Avoid hot, dry air from heat vents.
- Water: In water, change it every 2–3 days to prevent bacteria. In soil, keep the soil consistently moist but never waterlogged.
- Soil: Use a lightweight, well-draining potting mix if planting in containers. Add a bit of compost for extra nutrients.
One simple trick: Place a clear plastic bag loosely over your jar or pot for the first few days. This creates a mini greenhouse that speeds up sprouting. Remove the bag once you see green shoots.
Can you replant spring onions after you cut them?
Absolutely – in fact, that is the whole idea. After you harvest the green tops (cutting them about an inch above the bulb), the bulb will grow a new set of leaves. You can keep cutting and regrowing several times. Each crop is a bit smaller, but you can easily get 3 to 5 harvests from a single bulb if you treat it well. For best results, rotate which bulbs you cut from – let some recover while you harvest others. If a bulb starts looking mushy or the leaves look pale, discard it and start a new one.
Should you replant spring onions in soil or water?
Here is a simple comparison to help you decide:
| Method | Pros | Cons |
|---|---|---|
| Water | Easy, no dirt, clear roots, quick regrowth | Limited harvests, thinner stalks, may need more bulb replacements |
| Soil | Nutrient-rich, larger bulbs and thicker greens, more regrowth cycles | Takes more space, requires watering, potential for pests or rot if overwatered |
For most home growers, a hybrid approach works best: start bulbs in water to get them going, then transfer to soil after about one week for stronger, longer-lasting plants. If you only want a few green tops for garnishes, water is fine. If you want a continuous harvest for salads and stir-fries, use soil.
How to care for replanted spring onions for continuous harvest
To keep your spring onion supply steady all season long:
- Water regularly – check the soil moisture every day. Stick your finger in; if the top inch is dry, water it.
- Fertilize lightly – once a month, add a half-strength liquid fertilizer (like fish emulsion or a balanced 10-10-10) to the water or soil. Too much nitrogen makes them tall but weak.
- Harvest often – snip the greens when they’re 6–8 inches tall, but leave at least 2 inches of green above the bulb. This keeps the plant producing.
- Replace bulbs – after 4–5 harvests, the bulb will be spent. Add a fresh store-bought bunch to keep your rotation going.
- Watch for pests – indoors, the main troublemakers are fungus gnats (from overwatering) and aphids. Yellow sticky traps work well for gnats; a spray of water and a drop of dish soap handles aphids.
Pro tip: Use a pair of sharp kitchen scissors or garden snips for clean cuts. A dull blade can crush the stem and invite rot. For precision, consider a quality pair like garden pruning snips – they are handy for all small kitchen plant cuts.
What common mistakes stop spring onions from regrowing?
Even with easy vegetables, a few pitfalls can ruin your effort. Avoid these errors:
- Cutting too much green at once – never cut more than half the leaves. The bulb needs some green to photosynthesize and recover.
- Letting the water get cloudy or smelly – bacteria kill the roots. Change water every 2–3 days without fail.
- Planting bulbs too deep in soil – the white part should be covered, but the top (where green shoots come out) must be above the soil line, or it rots.
- Ignoring light needs – a dim corner will produce pale, leggy, weak onions. Give them bright light.
- Overwatering in soil – spring onions like moist soil, not mud. Ensure your container has drainage holes. If you are using a decorative pot without holes, a self-watering planter with drainage can simplify care.
Can you replant spring onions year-round indoors?
Yes, spring onions are one of the best vegetables to grow indoors all year. They do not need a lot of space, and a small collection of jars or pots on a kitchen shelf can provide fresh greens even in winter. The key is enough light – in darker months, supplement with a dedicated indoor grow light for 10–12 hours a day. Without extra light, growth will slow down and plants may become leggy. With consistent care, you can have homegrown spring onions no matter the season.
Will replanted spring onions flower or go to seed?
If you leave them in soil long enough (2–3 months) and they experience a change in temperature or day length, they may send up a flower stalk. This is called “bolting.” The plant switches energy from leaf growth to flowering and seeding. The leaves become tougher and bitter once the flower stalk appears. To prevent this, harvest regularly and don’t let the bulbs get too old. If you see a thick central stalk starting to form, cut it off at the base – sometimes the plant will keep producing leaves for a while longer. But if you want seeds, let it flower and collect the tiny black seeds after the blooms dry.
What’s the easiest way to start replanting spring onions today?
Grab a bunch of spring onions from the store. Use the green tops for cooking. Place the white bulbs, roots down, in a small jar of water. Set the jar in a bright spot. Change water every 2–3 days. In less than a week, you will have new green tops to snip. That is all it takes. Want stronger, longer-lasting plants? After a week in water, transplant the bulbs into a pot of potting soil about one inch deep, water them, and keep them in a sunny window. Your kitchen will thank you with a constant supply of fresh, homegrown flavor.