Air Cooled 250w hps?

[hatecable]

Yo guys. Ive been reading myself sick on this site and am finally going to post a question. So if the info is out there, i missed it and am sorry for the repeat.

Im setting up my first hydro W/F single plant grow in a 2'x3'x6' cabinet. Ive been really trying to get my lighting dialed in before I make the purchase. I was looking at using a 250w hps with one of those solarmax bulbs if it can be found... though i havent found one for 250w yet.
Alternatively, I would probably use 8 27w Daylight CFL's for veg, then go for a normal 250w hps for flower. I want the nodes to be as close as possible, and on my first grow in soil, they were stretched out pretty bad(bag seeds though). The point is that im afraid even a 250w would be too hot to keep it close enough to the plant to keep the main stalk from growing like crazy before it makes new nodes. Am I just being paranoid? The "other" grow used 2 lowe's 70w hps for veg through flower and it was a constant fight to keep the damn thing out of the lights.

[hatecable]

i see several views but no responses. I guess i didnt actually state the question. Do you think a 250w hps would be a bit warm for a sealed cabinet that size with regular ventilation holes in the bottom and a 7 inch fan blowing out the top? Our house stays about 70 degrees and is almost constantly air conditioned. Its hot as hell in texas. If i need more, does anyone know of a system that has air passages built into the reflector for a 250w, or should I make the ol Bake-o-round cool tube?

[keeko]

what is your 'regular ventilation holes'?....how big are they and how many?

i myself use a 150 hps (also in texas) in the summer with fine results. But i have a 6 inch duct fan right above my light extrating the air. cool air in hot air out.

[hatecable]

i have a 8x24" vent 6 inches from the bottom with an ultra allergen filter across the back of it. Thats why the vent is so big, since the air will come in more slowly because of the filter. On the ceiling of the cab is a 7 1/2" hole with a 7" fan that I took apart for the motor and blades. It has a high and low setting like most household fans. I used it assembled on my last grow as a vent fan and it seemed to work just fine. Then again I was using 2 70w hps lamps in a different cab then too.

[killfrenzi]

I've got another couple techniques for ya:
-Reduce the 'swing' between night and day temps so that they are almost identical
-During the first 3 weeks of flower, use BLUE light (halide, daylight flouros, whatever) instead of RED light. Then, when the stretch period is over, go back to HPS to finish. This will make them stretch a LOT less.


This will help with stretching.

As for the ventelation. I am currently using a 250w HPS in a cabinent that is 21"x18"x56" So mine is a lil smaller than yours but I have the same heat issues. You seem to have a large enough passive intake though. If your house stays around 70 and you have a 7" exhaust fan mounted on top... I am pretty sure you'll be fine. If its of any concern you can always put your cab right in front of or behind your air duct. That should help suck some of that cool air in.

Also if you can or have one, a digital thermometer mounted about the same distance you would have the top of your plants from the light would get the hottest temps at the maximum height. And as long as those temps dont get above 88. You should be fine. Just watch for heat stress.

[hatecable]

Yeah, I did buy a digital environment meter, but I screwed up and got one that didnt have the cable running off of it. Stupid thing said to keep it out of direct sunlight so Im either going to have to make a shade for it or buy another one. Sure looks handy though.lol

[hatecable]

I just thought. I wonder if a combination of blue cfls and the hps would help reduce the stretch. I would think if the cfls were to either side of the hps and lower, the plant would be satisfied to reach the cfl's and slow down?