Saving allium seed
Spectacular flowers, terrible seed life. Allium seed is the shortest-lived in this catalogue — one to two years — so sow it the season after you save it.
- Life cycle
- Biennial (onion, leek) / perennial (chives)
- Pollination
- Insect-pollinated
- Isolation
- 800 m–1.6 km
- Seed life
- 1–2 years
- Yield
- 1 plant gives 200–600 seed
An onion in flower is one of the best sights in a garden: a globe of small white or purple flowers on a tall hollow stem, covered in bees. The seed that follows is plentiful but short-lived.
Onions and leeks are biennial, as with brassicas and root crops. Chives are perennial and set seed readily every year.
The protocol
- 1
Overwinter the bulb
For onion: grow the bulb, harvest it, store it over winter, replant in spring. For leek: leave the plant in the ground through winter.
- 2
Let it flower
A tall stem topped with a spherical head. It flowers over two to three weeks.
- 3
Bag the head
Allium seed is small and the heads shatter. Bag the head in fine mesh as soon as the flowers fade.
- 4
Harvest when black
Seed turns black and hard when ripe. Cut the whole head into a paper bag and let it dry there for a week.
- 5
Clean and sow soon
Rub the heads to release the seed and winnow. Store cool and dry — but sow within a year, because viability falls fast.
What goes wrong
Short seed life. Allium seed at two years old may germinate at 30 percent. Sow the season after saving.
Crossing. Onions cross with shallots and with other onion varieties. 800 m to a mile, or bag.
Bolting in year one. If your onion bolts prematurely it may still flower and set seed, but the plant was stressed — better not to save from it.
Saved seed from this crop?
Germination rates, what came true and what crossed — post it and let other growers learn from it.
All 14 protocols
Annual, biennial and vegetative crops all save differently. The index compares them side by side.