I've just harvested the last of my 2010 leek crop. Some leeks (sown 3/11 indoors) were put into a cold frame early April, these were harvested first, but the early planting out didn’t give them much advantage. The rest were planted outside 4/28 and most were harvested in December. Some of these had frozen and weren’t the best, ubut edible. Due to the semi-frozen ground, they were difficult to pull up. We used a garden fork and dig up lots of soil with them, then had to warm the dirt clods in the sun to in order to clean them up.
Other leeks started 5/16 indoors, were later planted outside. In November these were mulched well with hay and had a cold frame placed over them. They were harvested 1/30, after several warm days in the 50-60's. The soil was not frozen and the leeks were quite healthy. It would have been better to bury them deeper in soil before adding the mulch, for more blanching and protection. Otherwise, these are a nice winter treat. I’ve had several leek-mushroom quiches and potato-leek soups. I also dried some I have not yet used.