No to the card board! Totally rule that out.
wardrobe is a good space a 400W Hps would be better for that size 600w might get a bit warm.
You will need a inline fane and carbon filter cheap kit containing fan, filter & ducting can be picked up fairly cheaply on the interweb .
Avoid using foil for theses reasons -
- foil tears easily
- it crinkles and will cause hot spots especially when using HID but also applies to otherlights
- It conducts electricity ie you get a lose wire or short and touch the foil bzzzt pop zap.
Thing to use instaed of foil -
- Paint inside of wardrobe with flat white paint
- use balck and white plastic
- Use Diamond mylar, I prefer this to normal mylar as it doesnt cause hot spots
Making mistakes is all part of the learning processe, all the growers here have made mistake in thier time of growing, if they say they haven't , either they are lying or they are God.
Every grow is a chance to do better than before, just that fact you starting to grow is the biggest step forward you can take, once you start you'll never look back.
I wish you all the best with your grow and rest assured there always someone here to lend a hand, it aint called a family for nothing.
Peace
Growerz