I am not an expert but here is my two cents.

I think that Leeks flower/set seed in the second year, so you would probably eat them before then ( unless you are growing to collect seed )

In Boston ( Z6 ) you should be able to plant from seed now and have decent sized leeks by Thanksgiving. They are heavy feeders and may need additional boosts of foliar or top-dressing feedings.

I don't trim my leaves but others may. When you have a good sized root you may want to blanch ( cover with soil/straw etc.. ) to make the root stalk more tender.

hth

Thanks Namfon. I planted seedlings from a local gardener, so I guess they won't flower? That's one less thing to concern myself with (though I love allium flowers!)

I will take your advice and feed and maybe cut back some of the foliage so that I can heap more organic material. They look good (if small) so far.

Thanks again!

One of our favorite August dishes is Corn,Crab and Leek soup. The sweet corn and leek come to the farmer's market at the same time, I can provide the leeks this year I hope!
yum!

If they flower they will be no good for eating. The flower stalk is tough and stringy and will ruin the middle of your leeks. You say you want to heap organic material but remember that anything around the leeks is likely to get into the layers so you will have a terrible time washing them for cooking. Feed them but try to keep the mulch out of the leaves. Leeks are absolutely delicious at pencil thickness if you can bear to sacrifice some. They make a great salad steamed then cooled and dressed with vinaigrette.

I will add one more thing. IME some ( not all ) of my Asian leeks did flower ( bolt ) before the Western types.

This year I tried using the leek space for cover crop this spring and am planting seedlings in summer for late fall harvest. I have always planted in spring before so I don't know how it will turn out.

This is an interesting discussion to me. I am in zone 6 here, and I mess with the leek situation a little more each year - still trying to improve my outcomes. Always have planted as early in Spring as possible, but you know they just don't grow that much until July anyway, so maybe I should wait until later and it would be the same difference. A couple weeks ago I uprooted and separated a leek "incubation patch" that I had stuck in one corner of a bed while waiting for them to gain size and for a bigger space to become available. Then the pea vines got ripped out of one bed and I transplanted weensy individual leeks from the incubation patch over to that location. They took very well and although some of them are approaching that pencil size, most are still much thinner. This is the most leeks I have ever planted and I cannot wait to see how they will look in November what with all the nice room between them this time. I do usually dig them up in the Fall as I need them, but have even let them overwinter and harvested in early Spring before with no detriment. I imagine zone 5, being somewhat colder, is even better for leek production.

I am trying that incubation patch this year also. I still don't have a space to move them to, so I am watering well, a little organic soluble fertilizer and they are looking good. More than pencil size, actually. Maybe I can just keep treating them well and harvest them from the same spot!

An interesting aside: I let a few go to seed most years, partly for the seed, but mostly because they provide TALL, sturdy, interesting garden features. Everyone who walks by asks what they are. They aren't very colorful, but those big round balls might even be flower garden material. Maybe I will move a few seedlings to the flower garden and enjoy them next summer.