Onion
Also known as: Bulb onion · Allium cepa
11 types of onion
Day-neutral (Candy, Cortland)
100 daysBulbs anywhere. Great for gardeners at 35–37°N.
Long-day (Walla Walla, Yellow Sweet Spanish)
110 daysFor latitudes above 37°N — bulbs when days hit 14–16 hours.
Red (Red Wing, Redwing)
115 daysLong-day storage red. Sharp raw, sweetens when cooked.
Red Baron
115 daysLong-day storage red onion with deep burgundy rings. Firm, keeps well; sharper than the sweet reds.
Red Creole
110–120 daysalso: Allium cepa 'Red Creole', Red Creole Edible Onion
Short-day, pungent red onion with excellent storage quality. Best in southern and mild-winter regions.
Scallion / Green (Evergreen)
60 daysNon-bulbing bunching onion. Cut and come again all season.
Shallot
100 daysMultiplies into a clump. Milder, sweeter than onion — grow from sets.
Short-day (Texas Sweet, Granex)
110 daysFor the South (below 35°N) — bulbs at 10–12 hours.
White Lisbon (bunching)
60 daysClassic scallion — non-bulbing white-stemmed bunching onion. Cold-hardy; sow spring through fall.
White Spear Bunches (bunching)
60–80 daysalso: Allium fistulosum 'White Spear Bunches', Bunching Onion, Long Green Onion, Spring Onion, Welsh Onion
Does not form a true bulb — grown for long white shanks and green tops. Very cold-hardy and perennial in mild climates.
White Sweet Spanish
110–130 daysalso: Allium cepa 'White Sweet Spanish', White Sweet Spanish Onion
Long-day sweet onion with thick, juicy rings. Not a long keeper — use fresh or freeze sliced.
When & where
Germination
Spacing & depth
How to plant
Match the variety to your latitude — this is critical. Long-day for the North (14+ hrs), short-day for the South (10–12 hrs), day-neutral in between. Start seed indoors, trim tops to 3" for stronger transplants.
Grower's tip
When tops flop over, bend the rest, then lift and cure in a shady dry spot for 2 weeks.
Soil preferences
Loose, well-drained soil — bulbs rot in wet feet.
6.0–7.0
Compost + bone meal or rock phosphate worked into the planting hole.
Watering
Water in at planting, then only during active growth. Let bulbs go dry during dormancy.
Deep watering at the base. Avoid overhead watering after leaves die back.
Overwatered: soft, mushy bulbs at harvest; basal plate rot. Underwatered: small bulbs, thin necks.
Prefers top-watering — Top-water at the soil surface — keep the necks and crowns as dry as possible to prevent basal rot.
Temperature tolerance
60–75°F (15–24°C) during growth
40–60°F (4–15°C)
Hardneck garlic, shallots, and daffodils need a cold winter to bulb properly. Tender bulbs (dahlia, gladiolus) must be lifted in cold zones.
Container growing
Yes — great in containers
8+ in deep, wide enough to space bulbs 2–3× their diameter
Deep pot for tulips and daffodils; shallow bowls for crocus.
Detailed harvesting
For garlic and onion: dig when the bottom 3 leaves brown and top leaves still stand. Loosen with a fork, don't yank. Cure whole plants 2–3 weeks in a warm, airy, shaded spot.
Post-harvest storage & preservation
After curing, trim tops and roots. Store hardneck garlic 4–6 months, softneck 8+ months in a cool (50–60°F), dry, dark spot with airflow. Never in the fridge.
Culinary, medicinal & other uses
Culinary staple (allium bulbs), cut flowers (tulip, daffodil, lily), forced blooms indoors, or perennial garden color.
Medicinal or traditional uses are shared for interest only — this is not medical advice. Consult a qualified professional before using any plant medicinally.
Seed saving
Propagate by offset bulblets, not seed — bulbs mature much faster from a clove/bulb than from seed.
Not applicable when replanting clones. Cross-pollinated seed rarely comes true.
Save the biggest, firmest bulbs each year and replant. Over generations you build a locally-adapted strain.
Your zone's planting calendar
Pick your USDA hardiness zone and we'll estimate the key dates for onion in your area. These are regional averages — always check your own last-frost forecast before sowing.
From your kitchen — grow onion from what you already have
Two ways to grow from a store onion: replant a sprouting onion for green tops and eventual seed, or (much faster) buy 'onion sets' — tiny dormant bulbs.
- 1For green onions immediately: cut off the root end (1/2 in with roots attached) and plant it root-down in soil. Green tops in 2 weeks.
- 2For a full bulb crop: onions are biennials — a first-year bulb replanted in year 2 sends up a seed stalk. Let umbels dry, rub seed off, store cool.
- 3For real production: skip seed and plant sets or transplants in early spring, 4 in apart, 1 in deep.
Storage: Onion seed only stays viable 1–2 years — buy fresh or save annually.
My Onion notes
Onion seeds on hand
Track packets and loose seeds you already have. Private to your account.
Par level — leave at 0 for no alert. Anything below par shows on Seed Starting and your shopping list.
Order more seeds
Running low? Reorder from one of these seed stores.
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