Great to find another way to grow leeks! Thanks for the tip!
I discovered accidentally that I could overwinter leeks in my Zone 6A when I got the seedlings in too late so the plants weren't big enough to harvest come fall. I mulched them heavily and prayed. Sure enough they were big and strong the next spring and I let them go as long as possible before they started to form seed heads. You must harvest them before that happens. They were delicious. I have done this for two years in a row and am trying it again. So far despite our bitter one digit temps they look great.
Please keep in mind that leeks do have a long growing season. Any good vegetable seed company will carry leeks. Some to consider are Fedco, Scheepers, Johnny's Selected Seeds, Territorial Seed, Victory Seed, Pinetree, Sand Hill Preservation, Diane's Seeds, etc!
Here's an inspiration to grow your own leeks. This is the best vichyssoise soup ever although the whipping cream may kill you!!
Classic Vichyssoise For 4
INGREDIENTS:
1 tablespoon butter
3 leeks, bulb only, sliced into rings
1 onion, sliced (preferably sweet)
5 potatoes, peeled and thinly sliced
salt and pepper to taste
1/4 teaspoon dried thyme
1/2 teaspoon dried marjoram
1 bay leaf
5 cups chicken broth
1/4 cup heavy whipping cream
Snipped chives for garnish (optional)
DIRECTIONS:
1. In a large stock pot melt butter over low heat. Add leeks and onion, cover, and cook for 10 minutes.
2. Add potatoes and season with salt and pepper. Add thyme, marjoram, bay leaf and stir well. Cover pot and continue to cook for 12 minutes.
3. Add chicken stock and bring to a boil, reduce heat and cook, partially covered for 30 minutes.
4. Puree soup in blender or food processor and cool.
5. Prior to serving add cream. If you are serving this soup warm you need to reheat the soup slowly so that the cream does not change consistency.
but I will let you know how it goes. Pressure is sometimes a good kick in the rear for me to get something done! So thank you! 
