How to grow Onions
Allium cepa
Plant once, season everything all year.
Onions bulb up in response to day length, so match the type to your latitude: long-day for the North, short-day for the South, day-neutral almost anywhere. Easiest from sets.
Grow Onions with step-by-step help for your exact yard.
Start free in Seededly →Onions at a glance
| Sun | Full sun |
|---|---|
| Soil pH | 6.0–7.0 |
| Spacing | 4 in |
| Harvest | 90–120 days |
| Plant | Early spring |
| Note | Match day-length |
How to grow Onions, step by step
Plant early, right type
- Plant sets or transplants as soon as soil is workable.
- Choose long-day (North), short-day (South), or day-neutral to match your latitude.
Weed & feed
- Onions hate competition — keep the bed weed-free.
- Feed nitrogen early for big tops, which become big bulbs; stop when bulbing starts.
Cure for storage
- Harvest when tops flop and brown.
- Cure in a dry, airy spot 1–2 weeks, then store the necks-dry bulbs cool.
Onions problems & fixes
Onions — Small bulbs: what's wrong and how do I fix it?
Wrong day-length type, crowding, or weeds. Match the type to your latitude and thin to 4 in.
Onions — Onions flower (bolt): what's wrong and how do I fix it?
Cold stress on large sets. Use smaller sets and plant at the right time.
Onions — Rot in storage: what's wrong and how do I fix it?
Necks weren’t cured dry. Cure fully and store cool and airy.
Recommended onions varieties
- Yellow Sweet Spanish — All-rounder. Big, mild yellow keeper - the dependable choice.
- Walla Walla — Sweet. Famously sweet; eat fresh, doesn't store long.
- Red Wing — Red / storage. Deep-red and stores well into winter.
Onions month-by-month
| January | Off-season. |
|---|---|
| February | Order sets/seed. |
| March | Plant sets as soon as workable. |
| April | Tops grow; keep weeded. |
| May | Feed for big tops. |
| June | Bulbs begin to swell. |
| July | Bulbing — ease off nitrogen. |
| August | Tops flop — harvest and cure. |
| September | Cure and store the keepers. |
| October | Plant garlic/overwinter types. |
| November | Stored onions in the pantry. |
| December | Off-season. |