just some compost with perlite mixed in.
The size of the plant i put down to no heating in the box or anywhere near it, in fact it sit in a cupboard under the stairs!
So i think i could get better results if i added heat. But i want to keep cost to a minimum and post my results, then people can see what you can get from 2 strings of christmas leds (9.6w) and a wooden box lined with tinfoil !
I'm gonna improve it for next year, maybe a heat mat, brighter leds, bigger box, insulate the box are all options