Growing Green Onions, Leeks, and Shallots

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Three Alliums, One Delicious Garden

Green onions, leeks, and shallots are all part of the allium family—making them culinary cousins with similar growing needs, but distinct flavors and harvest times. Whether you’re tucking them into soups, roasting them whole, or sprinkling them raw into your favorite dishes, these garden staples are well worth the space in your raised beds.

Each of these alliums is cool-season friendly, relatively low-maintenance, and rewarding to grow. You can even plant them together if you plan carefully. Ready to get started? Here’s your complete guide to growing green onions, leeks, and shallots from seed to storage.

What’s the Difference Between Green Onions, Leeks, and Shallots?

  • Green Onions (Scallions): These are harvested young and used whole—bulb and all. They have a mild, fresh onion flavor and grow quickly.
  • Leeks: These tall, elegant vegetables grow thick white stalks and have a subtle, sweet onion taste. Leeks take longer to mature and are typically used in soups, sautés, and roasts.
  • Shallots: These are grown for their small, bulb-like clusters. Shallots have a flavor somewhere between garlic and onion and are often used minced in dressings, sauces, and roasts.

When & Where to Grow Green Onions, Leeks, and Shallots

All three crops prefer cool to mild temperatures and perform best in early spring or fall, depending on your growing zone.

  • Sunlight: Full sun is ideal—at least 6–8 hours a day.
  • Soil: Loose, fertile, well-drained soil with plenty of organic matter.
  • pH Level: 6.0–7.0 is ideal.
  • Spacing: These alliums like space between them—plan ahead to avoid overcrowding.

💡 Raised beds or mounded rows are ideal for alliums, as they improve drainage and make harvesting easier.

Starting From Seed vs. Sets

You can grow all three of these from seed, but shallots and green onions are often easier to grow from sets or transplants.

Green Onions

  • Seeds: Sow indoors 6–8 weeks before last frost, or direct sow once soil is workable.
  • Sets: You can also plant small onion sets and harvest them young.
  • Spacing: 1–2 inches apart in rows 12 inches apart.
  • Days to Harvest: 60–70 days from seed; quicker from sets.

Leeks

  • Seeds: Start indoors 8–10 weeks before last frost.
  • Transplants: Harden off before planting outside.
  • Spacing: 4–6 inches apart, rows 12–18 inches apart.
  • Days to Harvest: 100–130 days.

Shallots

  • Sets/Bulbs: The most reliable way to grow shallots.
  • Seeds: Can be used but are slower and less predictable.
  • Spacing: 6 inches apart in rows 12 inches apart.
  • Days to Harvest: 90–120 days.

Preparing the Garden Bed

Before planting:

  • Work compost or aged manure into the soil a few weeks ahead of planting.
  • Avoid planting where onions, garlic, or leeks have grown in the last 2–3 years to reduce disease risk.
  • For leeks, dig trenches 4–6 inches deep—this helps blanch the stalks for tenderness and flavor.

Planting Tips

Green Onions

  • Sow seeds shallowly (¼ inch deep).
  • For a continuous harvest, plant new seeds every 2–3 weeks in succession.
  • Keep soil moist but not soggy.

Leeks

  • Transplant when they are 6–8 inches tall.
  • Plant deeply (up to the first leaf) to encourage long, white stems.
  • As they grow, mound soil around the base to blanch the stems further.

Shallots

  • Plant bulbs pointy-end up, just below the soil surface.
  • Don’t bury too deep—shallow planting is key.
  • Mulch lightly to suppress weeds and retain moisture.

Watering and Feeding

  • Watering: Keep soil evenly moist, especially during dry spells. Avoid waterlogged soil.
  • Feeding: Side-dress with compost or a balanced organic fertilizer every 3–4 weeks. Leeks especially benefit from extra nitrogen.

Mulching & Weed Control

Use straw, shredded leaves, or grass clippings as mulch. This will:

  • Suppress weeds (important for shallow-rooted alliums)
  • Maintain soil moisture
  • Regulate soil temperature

💡 Be careful when weeding—these crops have shallow roots and can be damaged easily.

Companion Planting & Rotation

Good companions:

  • Carrots
  • Beets
  • Lettuce
  • Cabbage
  • Chamomile

Bad neighbors:

  • Beans
  • Peas
  • Asparagus
  • Other alliums (avoid crowding and cross-disease issues)

Rotation Tip: Rotate out of alliums for at least 3 years before planting them in the same bed again.

Pests & Diseases

Alliums are fairly pest-resistant, but a few issues can pop up:

  • Onion Maggots: Lay eggs at the base of plants. Use row covers early in the season.
  • Thrips: Tiny bugs that can cause silver streaks. Neem oil can help.
  • Rust or Downy Mildew: Fungal diseases in damp conditions. Improve airflow and avoid overhead watering.

Harvesting

Green Onions

  • Harvest when they’re pencil-thin or thicker, depending on preference.
  • Use scissors or pull from the base gently.
  • Can be cut above the soil line to allow regrowth.

Leeks

  • Harvest when stalks are 1 inch or more thick.
  • Use a garden fork to gently loosen the soil and lift them.
  • Trim roots and most of the green tops before storage.

Shallots

  • Harvest once tops yellow and fall over (like garlic).
  • Gently dig up bulbs and let them cure in a dry, shaded area for 1–2 weeks.
  • Store cured shallots in a cool, dry place for several months.

Storing & Preserving

  • Green onions: Store in the fridge, upright in a jar with water or wrapped in damp paper towels.
  • Leeks: Refrigerate unwashed. Use within 1–2 weeks. Can also be blanched and frozen.
  • Shallots: Store in a mesh bag or basket in a dry, dark area. Will last several months if cured properly.

Saving Seeds

Most home growers don’t save seeds from green onions, leeks, or shallots unless they’re growing open-pollinated varieties and are okay with long life cycles.

  • Alliums are biennials—they flower in their second year.
  • To save seed, allow plants to overwinter and flower.
  • Collect mature, dry seed heads and store in a cool, dry place.

Best Varieties by Type

Green Onions:

  • White Lisbon – quick-growing, great for early harvests
  • Evergreen Bunching – hardy and productive

Leeks:

  • King Richard – early and mild
  • American Flag – classic and cold hardy

Shallots:

  • French Red – flavorful, long storage
  • Dutch Yellow – sweet and mild

Additional Growing Tips for Success

  • Use row covers early in the season to prevent pest infestations.
  • Stagger plantings of green onions for a steady harvest.
  • Plant leeks deeply and keep hilling them as they grow to get longer white stalks.
  • Start shallots from sets for best results—seeds are unpredictable.
  • Don’t forget to label your plantings—many alliums look alike in early stages!

Growing green onions, leeks, and shallots in your garden adds incredible flavor, variety, and function to your kitchen and garden space. With a little care and planning, you’ll be harvesting aromatic alliums for soups, sautés, and seasoning all season long.