i'm using a 400watt hps which seems like alot for just a closet but we've managed to keep the heat down by using good ventilation. We water every other day or every 3 day depending on how much water the plants suck up, we just check the soil moisture everyday. In this grow we planted 5 and one of them died because it came out of the soil too soon and wasnt prepared for the light, but we wouldnt have been able to keep all 5 anyways so its not a big deal. You just have to keep spraying the plants when you plant them and theyre starting to come out of the soil. Just dont over water or else you'll drown the roots or make the soil too hard for the plant be able to push through. I just watched mine very carefully and when i first germinated the seeds in wet paper towel i would let them grow a decent size root before i plants them. Also make sure the heat isnt too high when theyre sprouting or they'll dry out really quick and jsut die. Also make sure to have good ventilation because if the plants not getting sufficient fresh air its just gonna die. And as for putting it infront of a window i wouldnt suggest it, you just get alot of light stretching usually and then when you put it under an hps it'll just die. I've only used HPS lights and its always worked out, but having a MH is also good, especially for vegging. I just think you need a proper light dude...its worth the money if your actually serious about growing. And make sure to remember the simple things like proper soil, good fresh water (i dont go near tap water) with a proper pH, and ventilation...it all adds up in the end to make great plants.