If that Miracle Grow has ferts in it already, it may be too hot for the young seedlings, and they might die. A more neutral soil would be better to start with.

If they survive, the ferts in the MG will run out in a few weeks. Many soil users prefer a more neutral soil so that they can add the nutrients themselves without having to guess how much nutrients are in the soil. Each time you re-pot with MG, you will have fresh soil with ferts again. Once you are in the final pots, the ferts will run out in maybe 2-3 weeks, at which point you can start giving it other supplements. The amount and frequency depends on the plants, some give is fert, water, water,... and some ferts, ferts, water,...

I don't know about the attic questions...but how about odor control? You say its a 10x10, are you gonna have walls around the space? Maybe just use some pvc and white/black plastic lining and duct tape. That would help with some light reflection issues too. The 400w will cover up to 4x4, maybe 5x5. Thinking for the future, aim for 5000 lumens per square foot. So, one 400w hps puts out about 50K Lumens and could cover 10 square feet nicely.

For cheap additional lighting, get some Y socket splitters and 46w cfls from walmart.
bigtopsfinn Reviewed by bigtopsfinn on . My First Grow - Seeking criticism/advice! Hello Everyone, As i had stated in my intro, I plan on sharing my first grow experience with you all. I live in maryland to give you an idea of the climate, however, the plants will be growing Indoors in an attic. All of my questions are in bold. First a couple questions: Do attics typically face humidity problems? Does insulation/insulation dust have any effect on the grow? It is a large attic, essentially its another floor, just not finished off. The first thing I did on my Rating: 5