Estimated grow time

I realize that Northern Lights and White Widow are both popular strains to grow for indoor growers so hopefully someone can give me a ball park answer....i am trying to plan out a vacation for this spring but im to afraid to book anything when i dont know when my plants are going to need harvesting....im pretty sure that i've already screwed my spring break...im only trying to grow one of each, about 3-3.5 feet tall...using cfls to grow...can anyone give me an educated and hopefully experienced guess as to how long it will take to grow from seed to harvest? any answers would be great...thanks