I did that with an old window last year. It does work well. I have just been keeping it inside under a 45 watt cfl, about an inch and a half away or so. Seems to be growing nicely. I have had it under 24 hours of light this first 13 days, I just shut the light off, I will turn it back on in about 4 hours. I'll do that until I put it outside for good in about a week, maybe less. I have to get into its final spot soon. It will stay in the pot, just not inside. Its going to grow most of its life outdoors. If this thing keeps growing like it is now, it could easily reach 3 feet. Im judging by my fast bud, and what size it was at this age, and it is around 20 inches, maybe more now. I guess it really depends on when it shows signs of flower, longer veg time, the bigger it should get. Unless its just a runt like some of them are, which I doubt. Its growing too fast for that.