8 cm would be about 3 1/2 inches. 8 mm would be about 1/2 inch! About temps- if you're happy, they're happy. :thumbsup:

I have my seedlings under CFLs by night and on a window sill by day. There is some semi-translucent white plastic on the windows to block the direct view of them, but still let most of the sunlight. I start in deep blue plastic12 ounce cups. I can see the roots, but it's dark enough that the light doesn't bother them.

They then go to 32 ounce cups (that litterers have tossed and I picked up). I LST them to make all the bud sites get their share of the light. Eventually they go to one gallon pots and finally to 19 gallon tubs.

Hit the Grow stickies and anything by stinkyattic ("She da queen grower!" :thumbsup. Have fun! - Granny:hippy: