How long do i need to grow?

So i currently have 1 week old cannabis plant growing under 3x 27w cfl's
My question is - how long do i need to veg it?
In august i'm moving away from my current place and obviously i cannot take the plant with me.
Strain - White Widow
grow space:
36cm wide
56cm deep
41(57 not accounting lights)cm high

First grow.

Seems like changing thread title duplicates it.
ignore this thread.