I usually plant Christmas week under lights and with heat. I have some on a North facing windowsill in windowboxes now that were planted some time ago under lights, Just an experiment to give me something to do, I have flowers now, they were lanky and I trenched them when they got to their final position, still a bit lanky but they are growing well, all fast maturing types that don't grow tall. Much better than I expected them to be.
Usual ones are waiting till the end of January this year.
You can have wall of water thingies shipped over from thre US, postage is not much but they themselves are pricey I think.
If anyone needs a link I can find you one XX Jeannine