Hey Guys I need some advice, should I just put a 250w Hps light with ceramic MH bulb in a closet with a few fans blowing on it? and hopefully it wont get too hot orshould I
stick a growtent in my closet with the light and a 6" duct fan to exhaust the air??? in both ways part of the closet door will be kept open for ventilation.What would you do thanks for any advice!! later
I'm probably not the only one who has tried this with a grow cab, but leaving the door partially open for ventilation actually makes my cab hotter. The few times that I bi-accidentally left the door open on one of my side by side identical 250mh cabs the Ranco temp control thermostat would show me some impressive (read high) numbers. Probably due to the fact that the air being sucked by the exhaust fan finds the shortest path of least resistance that will usually not be the path coinciding with the hot air above your light, therefore allowing the hotspot around your bulb to expand in diameter. Take my advice (based on my experience) intake air from one side of the cabinet just above your light just by cutting a 4" diameter hole (do not blow air into the cab) In the case of a mini-cab, leave about 4" above your light fixture as an air plenum. Now exhaust air from the opposite side of your plenum just above your light and directly across from your intake point. You want your inlet to be a little smaller than your exhaust diameter.
Also, because this is a mini cab , chances are you don't have room for an oscillating fan, so you will poke a small hole a few inches below your soil line (or reservoir line) at the most extreme possible diagonal point in respect to the exhaust port. This will facilitate some air agitation near the bottom of the cab. If you are putting a reservoir inside the cab, take care to never make air intake holes on the bottom where air would make friction against your reservoir container because that will change your res temp. This isn't a concern if you are in a warm tropical zone, but if your intake air is ever cold, bottom air inlets would also cool your reservoir. .02