i say start em off in a big pot,ive done the same,im on my first grow indoors and transplanted from 5 1/2" pots into 5 litre tomato pots on sunday and already have roots showing through the drain holes in the pots next time im deffo startin of in a pot big enuff for its life time,i dont want to cause more stress by transplantin them again to a bigger pot although i reckon im gonna have to within a week or 2