everybody says the light that the sun gives off is so much thousands of lumens even on a cloudy day, then why doesnt everybody just put their plants at a window or outside. its more powerfull than a hps isnt it ??
Light period and manipulation. Could you imagine moving a weed plant all over your house searching for the sunny windows? Also what if the house has low E glass. Or what if......
Also due to light refraction, reflection, and diffusion caused by the glass will reduce the amount of lumens directly given to the plant.
Inside grows better under HID
Outdoor grow requires a certain amount of direct sunlight to maximize the plants growth. Also having a 5' plant in your window is not the most stealthiest way to grow. IMHO
I walked by a house the other day and it had a pot plant about 18" high in the window and I was thinking about smashing the glass and taking it(second floor) but it's this cute little blonds house. Plus you can go to jail, but you know what I do in the summer months only. I put my plants in my backyerd in pots from 6am-6pm then bring them in to the house somewhere 100% dark for the next 12 house to bud my plants, but it also good to have a 400 watt hps.