How to Save Onion Seed

It’s the middle of Spring and I should be furiously planting out seedlings, but with high temperatures and hot winds on this particular gardening Sunday, ‘transplant shock’ would be a death sentence to small plants under these conditions.

Fortunately there is another job where these same conditions demand action; collecting onion seed for the vegetable seed collection.

Onions (Allium cepa) are a hardy biennial from the southern parts of Russia and Iran. Biennials are plants that produce vegetative growth (and in this case, onions) during the first growing season, slow down through a period of cold weather, go to seed in the second growing season, and then die.

Spring onions (Allium fistulosum) originated in the Altiac Mountains east of Mongolia and were probably cultivated first in China and Japan, entering Europe from Russia with invaders in the Middle Ages. Spring onions are a perennial, meaning that they should last year after year, even if neglected somewhat. This is a useful skill in an edible garden, as they produce faithfully in a quiet corner.

So I have both types of onions – biennial and perennial – and both are going to seed in this second Spring after planting. They have shot up on leafless hollow stems, produced the pretty spherical mauve flowers typical of alliums, and the plant heads are now coming to seed at different rates. The heat is helping, but strong winds will knock them down and scatter the seed onto the soil, so I’m out there with the scissors cutting off the browned seed heads where the seed capsules have opened and the black seeds are visible.

One can go to some trouble here bagging and drying these seed heads in a warm dry shady place, but I find that just tapping the heads into a plastic tray produces adequate levels of seeds under these weather conditions. These will be left in open air in the shade for a few days to allow the small insects to escape and to dry the seed a little further before they go to the storage tins. The fine chaff is blown gently away.

Historical source: The Seed Savers Handbook