How to Grow Top Set Onion
Wikimedia Commons
Top Set Onion
Allium cepa var. aggregatum
vegetableTop set onions, also called Egyptian onions or walking onions, produce small bulblets (sets) at the top of tall stems instead of underground. These unusual onions are perennial in mild climates and can literally 'walk' across the garden as the weight of the top sets bends stems to the ground, where they take root and multiply.
When should you plant Top Set Onion in your zone?
Get a personalized planting timeline — when to start seeds, transplant, and harvest — based on your USDA zone and local frost dates. Free to start.
Example Top Set Onion timeline · Pittsburgh, PA (Zone 6b)
-
Plant Top Set Onion
Around Apr 17Near Pittsburgh's average last spring frost.
-
Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
-
Harvest Top Set Onion
Around Jul 16≈ 90 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Top Set Onion dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Zones 4-8; best as perennials in zones 5-7
Sign up free to see if Top Set Onion grows in your zone — and get a personalized planting timeline.
Get my Top Set Onion timeline →Growth Stages
Establishment
3-4 weeksYoung plants develop 3-4 leaves and begin forming the underground base bulb
Keep soil consistently moist. Thin seedlings if necessary. Provide full sun exposure.
Vegetative Growth
4-6 weeksTall hollow stems with strap-like green leaves emerge; plant grows 12-24 inches tall
Water regularly, maintain adequate spacing to prevent crowding. Fertilize monthly with balanced fertilizer.
Top Set Formation
3-4 weeksFlowering stem elongates and small bulblets (sets) cluster at the top, initially appearing as tiny green bulges
Continue watering. Do not pinch off tops. Reduce nitrogen fertilizer to encourage set hardening.
Set Maturation
2-3 weeksTop sets develop papery outer layers, turn brown, and become increasingly papery and distinct. Stem begins to weaken under their weight.
Reduce watering to allow sets to cure. Stems may naturally bend to ground.
Harvest & Storage
Ongoing through seasonTop sets are fully mature with crispy papery skin. Underground bulb may also be ready to harvest.
Cut mature tops with sets, or allow to fall and propagate naturally. Store in cool, dry location.
Common Pests
-
Use row covers over young plants, remove infected plants, practice crop rotation, apply neem oil if needed
-
Increase humidity, spray with water, apply insecticidal soap, use neem oil
-
Use reflective mulches, remove affected foliage, apply neem oil, encourage beneficial insects
-
Use disease-resistant sets, practice crop rotation, disinfect tools, avoid overhead watering
-
Ensure well-draining soil, avoid overwatering, use disease-free sets, remove infected plants immediately
Uses
Fresh onion flavor
CulinaryTop sets have a mild, slightly sweet onion flavor suitable for fresh use in salads, pickling, or light cooking. The small bulblets can also be used like pearl onions or small garnish onions. [source]
Long-term storage & preservation
CulinaryTop sets dry well and keep for several months in cool storage, making them excellent for winter use. They can be pickled whole or sliced for extended preservation. [source]
Garden propagation & self-seeding
HouseholdTop set onions are exceptional for gardeners who want a perennial crop. Sets naturally fall and propagate, creating a 'walking onion' effect that can fill garden beds with minimal replanting effort. [source]
Novel & ornamental appeal
HouseholdThe distinctive tall stems topped with clustered bulblets make top set onions visually striking in the garden, serving dual purpose as an unusual edible and an interesting landscape feature. [source]
Immune & digestive support
MedicinalLike other onions, top sets contain sulfur compounds and quercetin with reported antimicrobial and anti-inflammatory properties, traditionally used in folk remedies for colds and digestion. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Top sets mature 90-120 days after planting. Harvest when papery outer skin fully develops and turns tan/brown, typically in mid-summer. Cut the entire top set cluster with 2-3 inches of stem attached. For underground bulbs, harvest when foliage yellows and falls over. Store top sets in a cool (50-60°F), dry location; they can be replanted immediately or stored for spring planting.
Fun Facts
- 🌱 Top set onions are also called 'walking onions' or 'Egyptian onions' because the weight of the mature bulblets at the top causes the stems to bend down until they touch the soil, where the sets take root and appear to 'walk' across the garden, expanding the patch year after year.
- 🌱 Unlike most onions that are grown as annuals, top set onions are perennial in mild climates (zones 5-7) and can be left in the ground year-round where they'll regrow from the underground bulb each spring.
- 🌱 Top set onions produce no seeds—they reproduce entirely through the bulblets that form at the top, making them a true asexual crop that breeds 'true' without variation.
Join 30,000 gardeners planning their gardens with LizPlants.
Get your personalized Top Set Onion planting timeline
Tell us your zip code and we'll calculate exactly when to start Top Set Onion seeds, transplant seedlings, and harvest — based on your USDA zone and local frost dates. Includes calendar reminders and printable task lists. Free to start.
Get my Top Set Onion timeline →