This Spring I left half a dozen leeks go to seed. I now have some wonderful seed heads which are covered in bees. I was reading in a veggie magazine last week on how to propagate from "leek pips". Apparently you leave the seed heads until the Autumn when the little seeds start to sprout from the flower. This flower head then has little green leeks growing out of it like a mane of green hair! The idea is then to pot them up and overwinter them in the greenhouse for early leeks next year. Will give it a go.