Leeks

I have 24 leeks I have grown from leek 'grass' planted in a seedtray of modules on the kitchen windowsill. They are romping away now and rather than put them in the cold greenhouse I am contemplating leaving them where they are for a while. My logic is if they get a little bit 'drawn' that shouldn't be too much of an issue because the white part of the leek is mainly what I eat and blanching will give more white stem.
I put them in the greenhouse last year and the bitter cold froze the leeks in the modules, even indoors. After subsequently planting them out later in the season they bolted straight away and had to be dug up. All was not lost as by then they were of a useable size.
If I can cossett them a bit on the windowsill and they don't get ridiculously leggy I am hoping they won't bolt quickly when planted out. If we have a bit of sunshine I can probably put them outdoors during the day and bring them in for the night.
That's what I like about veg gardening it can be very experimental and Mother nature dictates how far she will let you go.