I was just looking through Thomas Etty's catalogue, and I was struck by this:
Long Winter (Poireau Long d'Hiver). By 1873 "Société d'horticulture et de viticulture d'Epernay." "This variety withstands the winter well & is particularly suitable for planting in Autumn."
I assume they'd have been planted in the autumn for harvest the following year, but does anyone know more?
I would assume they would act similar to overwintered onions, just being harvested earlier.
I'm not sure about harvesting earlier; the onions are different varieties bred for early ripening. It might be a way of growing bigger leeks, though. I may try it next year.