"TheScullster"wrote

The location is East Yorkshire - 4 miles from the end of the Humber
Bridge.
The leeks must have been in 6 weeks.
To improve their chances, I potted them on about 2 weeks ago in general
compost - to a deeper pot thinking they might need deeper for rooting.
How long should they take on a window sill to get to pencil thickness?
Or do they need planting out into open ground when in blade-of-grass mode?

We plant our seed outside in an old plastic 50gal water tank full of compost
(mainly for carrots) and then transplant then into their final positions
after making the holes. Never grown them indoors or even in our greenhouse,
perhaps that is your problem.

--
Regards
Bob Hobden
W.of London. UK