Hey guys I just ordered a 400 watt mh light and I'm not sure what to expect and I don't know anything about them. Can they start a fire if it's close to my wall? How far away should it be, ect.. Can someone please tell me everything I should know about them.
Well besides the MH light you will also need a ballast to run it. When buying a ballast try to get one that runs both MH and HPS. I would also recommend a cool tube if it is in your finances, as well as a fan to extract the hot air the H.I.D. light will generate. As far as running to close to your walls and or ceiling, if you are using a hood with your light you should be O.K.. Check out some cabinet builds and how others have run their exhaust out of their cabinets or tents. If you are not running a hood with your 400 which is not recommended then you may have to take precautions and keep a fair distance(maybe 2 feet or more) from your walls and ceiling. Best advice here is to light her up and monitor it for several hours or a full cycle if you can. Better safe then sorry.
These are my opinions based on information you have provided, I am NOT an electrician, nor qualified home inspector.
Im going to assume you have a fan ducting possibly even a carbon scrubber to go with that cool tube.and that you will be swapping out the mh for a hps come time to flower and cut straight to the questions you asked. could it start a fire? if incorrectly installed, hell yes. I would allow about 18 inches from anything flammable like walls etc. and the same distance could be said for your plants but this will depend on the efficiency of your cool tube at the moment my 600w cool hood with an 8 inch extractor fan is very cool and allows the plants to get very close but the plants are starting to get bleached from over exposure to the light mind you they are about 6-8 inches from it which I do not recommend.
Basically you want the light as close to them as possible without burning or bleaching them basically if it feels hot on your hand it will be too hot for them and any closer than about ten inches with a 600w I experience bleaching.
That's right no cool tube there,which is fine but due to the heat emitted it will need at least that 18 inches or so. A carbon scrubber is attached to your inline fan to help remove any unwanted smells for air exiting your tent.
She will spread her roots out once in the new soil. You should fill your pots to within an inch of the top of the pot though, more soil for roots to grow. The inch you leave on the top is to allow you to add sand if you get soil born insects, other then that you could go right to the top of the pot.