Well here we have the root structure of one of my Leeks. As you can see there is a fair amount of healthy white roots starting to bottom out of the pot. The pots they were in were 7cm square pots so I've moved them up to 1/2 litre pots.
Here they are in the growing area. This is just a box constructed of "sterling board" with insulation foil stapled to the inside. My T5 light is suspended from the top, and is on a timer giving 9 hrs of light. The thermostat you can see in the photo control's my tube heater which is at the bottom of the chamber and is set to come on when the temp falls below 12 degrees C. The leeks are growing steadily and most are three inch to the button. As these leeks are not Pendle or Pendle Improved I have been advised by a number of more experienced growers that there is no need to collar them at this time. They currently are getting one spray of SB invigorator per week. So fingers crossed they keep growing on.