How to Grow Scallions (Green Onions): Complete Guide

How to Grow Scallions (Green Onions): Complete Guide

Scallions — also called green onions, spring onions, or bunching onions — are the most useful allium in the kitchen and one of the easiest vegetables to grow. They are ready to harvest in just 8 weeks from seed, grow in any container on a windowsill, and famously regrow from kitchen scraps in a glass of water.

Whether you are a first-time gardener looking for an instant win or an experienced grower wanting a continuous supply of fresh green onions, scallions deliver. They grow year-round indoors, tolerate partial shade, and take up almost no space.

Quick Facts

Three Ways to Grow Scallions

Method 1: Regrow from Kitchen Scraps (Fastest)

The viral kitchen hack that actually works:

1. Save root ends from store-bought green onions (the white part with roots, about 1-2 inches)
2. Place in a glass of water with roots submerged, green tips above water
3. Set on a sunny windowsill
4. Change water daily to prevent slime
5. Green shoots appear in 2-3 days, harvestable in 7-14 days
6. Cut greens as needed — they regrow 3-4 times before losing vigor

Upgrade: After roots develop, transplant into soil for stronger, longer-lasting regrowth.

Method 2: From Seed (Best Long-Term)

1. Sow seeds 1/4 inch deep, 1/2 inch apart, in rows 12 inches apart
2. Seeds germinate in 7-14 days
3. Thin to 1-2 inches apart when 3 inches tall
4. Harvest at 50-65 days when pencil-thick
5. Succession sow every 3-4 weeks for continuous supply

Method 3: From Sets (Fastest Outdoor)

1. Buy onion sets (small bulbs) labeled for green onions
2. Plant 1 inch deep, 2 inches apart
3. Harvest in 30-40 days when tops are 8-12 inches
4. Fastest outdoor method — even faster than seed

Best Scallion Varieties

Evergreen Hardy White — The classic bunching onion. Non-bulbing, very cold-hardy (perennial in Zones 5-9). Regrows after cutting. 60 days.

Tokyo Long White — Japanese variety with long, slender white stems. Mild, sweet flavor. 65 days. Excellent for Asian cooking.

Parade — Dark green tops, uniform, slow to bulb. 60 days. The best variety for succession planting.

Red Beard — Striking red stems with green tops. Mild flavor. 60 days. Beautiful in salads.

He Shi Ko — Very hardy, overwinters in most climates. Thick stems, strong flavor. Perennial. The best for permanent patches.

Growing Guide

When to Plant

Spring: Sow 4-6 weeks before last frost (scallions tolerate frost to 20°F). Fall: Sow 8-10 weeks before first frost for fall/winter harvest. Year-round indoors: Any time on a sunny windowsill or under grow lights. Succession: Sow every 3-4 weeks for non-stop supply.

Soil and Location

• Any well-draining soil works — scallions are not fussy
• Full sun to partial shade (4-6 hours minimum)
• pH 6.0-7.0
• Containers work perfectly — even a 6-inch pot holds 10-15 scallions

Watering and Feeding

• 1 inch per week, consistent moisture
• Light feeder — compost at planting is usually enough
• Liquid fertilizer every 3-4 weeks for container growing

Harvesting

• Pull entire plant when stems are pencil-thick (8-12 inches tall)
• Or cut-and-come-again: Cut greens 2 inches above soil — they regrow 3-4 times
• Harvest outer stems first, leaving the center to keep growing
• Morning harvest for best crispness

Storage

• Refrigerator: Stand in a glass of water, covered with plastic bag. Keeps 2-3 weeks.
• Freeze: Chop and freeze in ice cube trays with water. Perfect for cooking.

Container and Indoor Growing

Scallions are one of the best indoor vegetables:

• Container: Any pot 6+ inches deep. Plant densely (1 inch apart).
• Windowsill: South-facing window, 4+ hours light. Water when top inch dry.
• Grow lights: 12-14 hours for best growth.
• Regrow method: Glass of water on counter — the ultimate zero-effort indoor garden.

Common Problems

Limp or Yellowing Tops

Overwatering or poor drainage. Let soil dry slightly between waterings.

Slimy Roots (Water Method)

Change water DAILY. Slime = bacteria. Rinse roots when changing water.

Bolting (Flowering)

Caused by heat or long days. Harvest before flower stalk forms. Flowers are edible but stems become tough.

Onion Thrips

Tiny insects causing silvery streaks. Overhead watering helps. Insecticidal soap for severe cases.

Frequently Asked Questions

Can I really regrow green onions from scraps?

Yes — it works reliably. Save the root end (1-2 inches with roots attached) from store-bought green onions, place in water on a sunny windowsill, and new green shoots appear within 2-3 days. Change water daily. You can harvest 3-4 times before the scrap loses vigor. For better long-term results, transplant rooted scraps into soil after 1 week.

How long do scallions take to grow?

From scraps: 7-14 days to harvestable greens. From sets: 30-40 days. From seed: 50-65 days. Scallions are one of the fastest vegetables. Succession planting every 3-4 weeks ensures you never run out.

Can I grow scallions indoors year-round?

Absolutely — scallions are one of the best indoor vegetables. They grow in any container 6+ inches deep, need only 4-6 hours of light (sunny windowsill or grow lights), and take up minimal space. A single pot on your kitchen counter can provide fresh green onions for months. The water glass method requires no soil at all.

Are scallions and green onions the same thing?

Mostly yes. "Scallion," "green onion," and "spring onion" are used interchangeably in most of the US. Technically: scallions are Allium fistulosum (non-bulbing bunching onions), while green onions can be young A. cepa (regular onions harvested early). Spring onions have a small bulb. In practice, they are all grown and used the same way.

Do scallions come back every year?

True bunching onions (A. fistulosum varieties like Evergreen Hardy White, He Shi Ko) are perennial in Zones 5-9 — they come back year after year and multiply into clumps. Cut-and-come-again harvesting lets you take greens without killing the plant. Divide clumps every 2-3 years to maintain vigor. This makes a permanent scallion patch one of the best investments in a kitchen garden.