Onion Sprouts
Onion Sprouts is a sprout in the Amaryllidaceae family. It grows well indoors with medium moisture, and is listed for USDA zones 2-13. Plants reach maturity about 5–14 days after planting and sit about 3 inches apart.
Varieties
1 from Seeds Now · sorted by days to maturity▸Onion5–14 days
Grows well with containers; Grows well with raised beds; Matures in <90 days; Start indoors; Super easy to grow
Onion microgreens (Allium cepa) have slender shoots with a mild onion flavor. Grow them densely indoors in a shallow tray, keep the medium evenly moist, and provide bright light after germination. They are slower than many microgreens and are usually cut when the shoots are a few inches tall.
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Plant spacing
In a square-foot bed, space onion sprouts about 3 in apart — that fits 16 plants in each 1-foot square (4×4). Wider rows or containers space the same.
Plan your onion sprouts planting
Add onion sprouts 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
Storing & preserving
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
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.
Floating row cover timing
ProtectionUnusual this time of year.
- Routine careCover at planting and seal the edgesstrong evidence — extension confidence
Lay floating row cover over the crop right at seeding or transplanting and bury the edges with soil so pests can't get under; don't cover ground where the same crop grew last year, since overwintered pupae would emerge inside.
- Routine careRemove at flowering for pollinated cropsstrong evidence — extension confidence
On crops that need insect pollination, take the cover off once flowering begins so bees can reach the blooms; on self-pollinated or leafy crops you can leave it longer.
Something looks wrong?
Describe what you see on your onion sproutsand we'll rank the likely causes — most likely first, least-invasive fix first.
Bacterial soft rot
Diseasesevere- 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.
- 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.
- 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.
Onion & garlic white rot
Diseasesevere- CulturalRemove infected plants and soil carefullystrong evidence — extension confidence
Dig and discard affected plants along with the surrounding soil to avoid spreading the long-lived sclerotia; clean soil off tools and boots, since this fungus can persist in soil for many years.
- CulturalAvoid moving infested soil and replantingstrong evidence — extension confidence
Don't replant alliums in known-infested ground; while rotation alone won't clear it, avoiding the area and not spreading contaminated soil is the most reliable home approach.
Leafhoppers & aster yellows
Diseasemoderate- CulturalRemove infected plants and weed reservoirsstrong evidence — extension confidence
Aster yellows can't be cured, so pull and discard plants showing yellowing and witches-broom, and clear nearby weedy hosts that harbor the phytoplasma and its leafhoppers.
- CulturalExclude leafhoppers with row covermoderate evidence — extension confidence
On young susceptible crops, a floating row cover keeps egg-laying leafhoppers off and lowers the chance of aster-yellows spread.
Leek moth and thrips on leeks
Pestmoderate- 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.
- 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.
Leek rust
Diseasemoderate- 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.
Onion thrips
Pestmoderate- 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.
- 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.
Cabbage & onion root maggots
PestmoderateUnusual this time of year.
- CulturalCover at planting with floating row coverstrong evidence — extension confidence
Place floating row cover over the crop at seeding or transplanting and bury the edges so flies cannot lay eggs at the stem base; do not use if the same crop grew there last year, since trapped pupae would hatch underneath.
- CulturalRotate and delay plantingstrong evidence — extension confidence
Rotate susceptible crops to a new spot each year and, where possible, delay planting to late spring to miss the main egg-laying window.