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Leek Microgreens

Allium ampeloprasum
Also known as: Garden Leek

Leek Microgreens is a microgreen in the Amaryllidaceae family. It grows best in full sun with medium moisture, and is listed for USDA zones 5-10. Plants reach harvest about 10–12 days after planting and sit about 12 inches apart.

Varieties

3 from True Leaf Market · sorted by days to maturity
  • Carentan10–12 days

    Heirloom; Non-GMO

    Carentan leeks are an excellent addition to dishes that need an extra oniony zest. This European plant has high yields. Tender white stems grow 8.5 inches long and 2 inches wide. Leaves are a medium dark green.

    View on True Leaf Market
  • Giant Musselburgh10–12 days

    Heirloom; Non-GMO

    Giant Musselburgh leeks are hardy in cold weather and easy to grow at home. Stalks grow 2-3 inches thick and 9-15 inches long and are tender and white. Leaves are medium dark green.

    View on True Leaf Market
  • Large American Flag10–12 days

    Heirloom; Non-GMO

    10-12 days. American Flag Leeks have an onion taste that can a burst of flavor to any micro salad. Long, slender greens look like miniature chives, and can be used as an onion substitute in most any dish.

    View on True Leaf Market
Family
Amaryllidaceae
Category
Microgreen
Form
Microgreen
Lifecycle
annual
Zone
5-10
Height
Spread
1–1.5 ft
Sun
Full sun

Plant spacing

1 plant per square footSquare-foot planting diagram: one leek microgreens fills a 1-foot square, spaced 12 inches from its neighbors.
1 plant per square foot

In a square-foot bed, space leek microgreens about 12 in apart — that fits 1 plant in each 1-foot square (1×1). Wider rows or containers space the same.

Water
Medium

Plan your leek microgreens planting

Add leek microgreens to a free GardenDraft plan and get sow, transplant, and harvest dates computed for your ZIP code — with a drag-and-drop bed layout and reminders when it’s time to plant.

Start your free plan →

At a glance

Days to harvest
10–12 days
From transplant or sow to first harvest
Harvest style
Harvest once
One main harvest
After harvest
Stores well
Holds (or improves) after peak
Frost tolerance
Hardy · to ~5°F
Lowest temperature the foliage usually survives
Succession
Re-sow every 14 days
Sow again at this interval for a continuous harvest
Germination
~60%
Typical minimum germination rate

Storing & preserving

Stores well in the right conditions. Cure 2–3 weeks, then store cool, dark, and dry — keeps for months.

  • Cure & store: Dry the necks/skins fully, then store in a cool pantry.
  • Freeze: Freeze chopped for cooking (texture softens).

General home-preservation guidance — for tested processing times and safety, follow the National Center for Home Food Preservation.

Growing timeline

When to plant and harvest leek microgreensPlanting timeline for leek microgreens, relative to last frost: start indoors from 16 weeks before last frost to 4 weeks before last frost; grow from 4 weeks before last frost to 3 weeks before last frost; harvest from 3 weeks before last frost to 2 weeks before last frost.Start indoorsGrowLast frostTransplant
Start leek microgreens indoors ~12 weeks before transplanting 4 weeks before last frost; first harvest 3 weeks before last frost.
Seed to transplant
70-84 days
Outdoor planting
-28 to -14 days vs frost
Propagation
Seed
Schedule anchor
Last Frost

Companion planting — with cited sources

From US/Canada cooperative-extension publications and peer-reviewed studies. Evidence-tier dots show how strongly each recommendation is backed: ●●● peer-reviewed mechanism · ●● extension consensus · traditional knowledge with a plausible mechanism.

Pairs well with (2)

  • CarrotEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionspest-deter

    Leeks emit sulfur-containing volatiles (allyl sulfides, propanethial-S-oxide) that disrupt host-finding by carrot rust fly (Psila rosae). Extension recommendations across the Northeast US, Pacific Northwest, and Ontario list leek alongside onion and chive as effective allium intercrops for carrot beds. The reciprocal benefit — carrot foliage masking onion fly (Delia antiqua) — is weaker for leek because leek itself is less susceptible than dry-bulb onion.

    Region: Most useful in maritime / cool-summer regions where carrot rust fly pressure is highest (Pacific Northwest, Great Lakes, Maritimes).

    Source: S1, S4, University of Guelph / OMAFRA

  • Common CabbageEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpest-deter

    Allium volatiles are frequently cited by extension as a partial deterrent to cabbage maggot (Delia radicum) and aphids on brassicas, though replicated yield trials are limited and effects are inconsistent. Leek's long season alongside the brassica crop makes it a convenient bed-mate.

    Source: University of Maryland Extension, S13

Sources cited

S1
Cornell University Cooperative Extension — vegetable production guides
S13
University of New Hampshire Extension
S23
University of Guelph / OMAFRA (Ontario)
S4
Oregon State University Extension Service
S9
University of Maryland Extension — Home & Garden Info Center

Care & troubleshooting— extension-sourced, with citations

When to feed, prune & water

Feed alliums in spring

Feeding
  • Routine careFeed nitrogen every 3 weeks during active growth· every 3 wks · ~9 wksmoderate evidence — extension confidence

    Alliums build the bulb from spring leaf growth. Feed a nitrogen source every ~3 weeks through spring, then stop once bulbs start to swell so they cure well.

    Source: UMN Extension

Floating row cover timing

Protection

Unusual this time of year.

Something looks wrong?

Describe what you see on your leek microgreensand we'll rank the likely causes — most likely first, least-invasive fix first.

Bacterial soft rot

Diseasesevere

Symptoms: mushy water-soaked decay of fleshy tissue; slimy soft rot of heads, bulbs, roots, or fruit; foul odor from rotting tissue; rapid collapse after wounding or in warm wet conditions; rot spreading in storage

  • CulturalRemove rotting plants and produce (manage, not cure)strong evidence — extension confidence

    Soft rot can't be cured once tissue breaks down; promptly remove and discard affected plants and produce so the bacteria don't spread to neighbors or other stored vegetables.

    Source: Cornell NYS IPM

  • CulturalAvoid wounds and excess moisturestrong evidence — extension confidence

    Harvest in dry conditions, handle gently to avoid bruising, control insects that create entry wounds, and improve drainage; cure and store bulbs and roots cool and dry.

    Source: Cornell NYS IPM

  • CulturalDon't overwater and rotatemoderate evidence — extension confidence

    Avoid waterlogged soil and overhead watering that splashes bacteria, and rotate away from previously affected fleshy crops to lower disease pressure.

    Source: Cornell NYS IPM

Onion & garlic white rot

Diseasesevere

Symptoms: yellowing and dieback of leaves; plants pull up easily; fluffy white mold at the base and on bulbs; tiny black poppy-seed sclerotia in the rot; spreads in patches in cool moist soil

Leafhoppers & aster yellows

Diseasemoderate

Symptoms: small wedge-shaped insects hop from leaves; stippled or yellowed foliage; with aster yellows: yellow stunted growth, witches-broom of thin shoots, deformed bitter carrots

Leek moth and thrips on leeks

Pestmoderate

Symptoms: whitish windowpane streaks or mottling on leaves (thrips); pale winding mines and holes in leaves; caterpillars tunneling in leaves and stems; distorted rotting foliage from secondary infection

  • CulturalCover and clean upmoderate evidence — extension confidence

    Cover plants with insect netting or row cover at planting to keep egg-laying leek moths and thrips off, and remove and destroy badly infested leaves and crop debris. Rotate alliums to a new spot each year to break the pest cycle.

    Source: RHS: Leek moth; RHS: Thrips on Garden Plants

  • OrganicWash off thrips or spray· every 1 wkmoderate evidence — extension confidence

    For thrips, hose plants down to dislodge them, or apply a labeled insecticidal soap or neem product per the label. For leek moth caterpillars, a labeled spinosad or Bacillus thuringiensis product applied per the label when young larvae are active can help.

    Always follow the product label — it is the law.

    Source: RHS: Leek moth; RHS: Thrips on Garden Plants

Leek rust

Diseasemoderate

Symptoms: bright orange raised pustules on leaves; yellowing around the spots; heavily infected leaves drying and dying back; reduced size of usable shank

  • CulturalImprove airflow and remove infected leavesmoderate evidence — extension confidence

    Leek rust is a fungal disease favored by damp, crowded conditions and lush growth; space plants well, avoid over-feeding with nitrogen, and remove badly affected leaves. Mild cases usually still produce a usable crop, and rotating alliums each year helps prevent buildup.

    Source: RHS: Leek rust; UMN Extension: Growing leeks

Onion thrips

Pestmoderate

Symptoms: silvery streaks and flecks on leaves; tiny slivers that scatter when disturbed; worst in hot dry weather

  • CulturalOverhead-water and remove debris· every 3 days · ~3 wksmoderate evidence — extension confidence

    Thrips dislike moisture; overhead irrigation and weed/debris cleanup reduce them. Reflective mulch deters them on young plants.

    Source: UMN Extension

  • OrganicInsecticidal soap/spinosad - label use only· every 1 wk · ~3 wksmoderate evidence — extension confidence

    For heavy pressure a labeled soap or spinosad on a weekly schedule helps. Follow the label.

    Always follow the product label — it is the law.

    Source: UMN Extension

Cabbage & onion root maggots

Pestmoderate

Unusual this time of year.

Symptoms: young brassica or onion transplants wilt and stunt; bluish off-color leaves; white legless maggots in roots; rotting tunneled roots; plants pull up easily