uk 2010 outdoor grow

hi all,this year im planning to grow my seeds i have about 10 and they are all a sativas strain.

i waz wondering if it would be a good idea to put them under clf for a few weeks before they go outside to get em started.

does anyone kno what month to put them outside in my green house?,i live in the uk so i waz thinking of putting them outside at late feb/march because its still cold here.

thanks