Discussion in 'Growing Marijuana Indoors' started by charlie067, Mar 21, 2003.

  1. ok i just messered my grow room its 7 ft high and 6x5 width and lenght i just hooked up a 400watt hps how many inche's should it be from the plants i put it a lil over 20 inche's from the plants but im wondering about heat build up i have a fan on the plants and i have a door in the grow room that opens where cool air comes out and a door to get into the grow room that opens from the outside i want to know

    how many inche's away from the plant is the best with 400watthps
    and will my 7ft ceiling and my width and lenth is 6x5 will i get alot of heat build up i only have 4 plants under the hps
    plz awnser soon as posiable
    thank you
  2. 18" from lamp to plant is the normal.

    if ur worried about heat build up and ur light has a remote balast then put the balast outside the grow room and run the cable in to ur lamp.

    if it still gets to hot then its time for an extractor fan of some kind.
    good luck with the grow
  3. your room is to big for 400 watts the most I would go is 7x4x4

  4. eh? his room is only 5' wide, 400w will easy light 4'x4', that only gives him 6" either side of his plants to let the air get around and him aswell if he needs to tend to them.

    he allready has the room and the light so it wudnt b worth getting a bigger lamp, that wud just make any heat problems he has or mite have worse.

    if he finds later he dont have enough light a few fluros on the walls wud sort that. and anyway he only has 4 plants.
  5. Yes that all sounds fine. I take it that you have incorporated some method of raising or lowering the light ?.In this space I would start about 10 plants- if you get more than 5 females you can always find ways of sharing the available light between them.
  6. do the math a 6x5 room is 30square feet and 400watts aint gonna cover it with a room say 4x4 its a tighter fit but you will get so much more reflection off your walls as long as there painted flat white or u use a mylar youll have much tighter and bigger buds if ya go smaller

  7. 40 cm clearance. Heat shouldn't be a problem if you have run an oscillating fan to keep good air flow in the room.
  8. charlie067 stinkbud is right you might want to scale your room back some you should have 30watts per square foot and a room 6x5 is 30square feet which inturn you would need 900watts so go down to a 4x4 thats 16 square feet times 30 watts 480 watts so dont go any larger and what would be the sence of putting more fluors in there there gonna just take up more room and they dont bud for shit
  9. he did say 6x5= 30 sq feet = a min of 60,000 to optimal of 90,000 lumens.....a 400w HPS will emit 45,000 lumens, and the rule for distance is......400w=400mm= approx 16"......Peace out.....Sid

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