I don't know if you can draw a correlation between onions and leeks but the overwintered leeks started flowering about 3 weeks ago and I'm seeing / feeling the first seeds from the flowers today. It looks like they have another week or so on the head before they'll be ready for harvest.

GardenLad,
A friend grows Sweet Stockton Red seed every two years. No records. He says that from full bloom, 3 to 4 weeks will see mature seed. Depending on how hot, etc. I have grown it out but never recorded the time. I do have a leek that I am watching. Looks like Makaul is pretty close.

Thanks, guys. They've been in flower for about 2 1/2 weeks, so I'll start monitoring them more closely.