kbean

Soon im gonna need a flower light for my 12 babies. Im planning on planting em into soil, in rows of 3x4, and grow them oldschool. In theory i understand that 2x400w HPS would be as good as 1000w for this. But i have no experience so, what do you experienced growers say ?
The 600w are out of the question on the moment because my local retailer has none, and it takes about 3 weeks to get any. I need it sooner.

Ripcord

Too bad about the 600 situation, they are the most efficient, and 2 digital 600 use about the same wattage as a regular 1000. I sold my 1000 and bought the digital 600. You can grow a nice stash with a 600. I'm upgrading soon to 2 of em. Theres a noticeable difference in canopy penetration between a 400 and 600 too IMHO Good luck and good growing.

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kbean

but hows the heat? My room is about 3x3 meters (about 10x10 foot), The door is closed all the time so ventilation would be minimal. Would 2x600 or 1x1000 be max to fit in there ? The ambient temp is about 22c (72F)

DarkFox

I fully agree with everything Rip said...

In answer to your question, there's differing opinions on here.... I'd personally prefer the better footprint of 2 x 400watters than 1 x 1000... but then you'd need to keep them nice n short 'cause the 400's wouldn't have the penetration power of a 1k... If you wanna grow a few monsters then there's a good arguement for the POW! of 1k'ers, have a look at Jamesgang's and Spirit of Bear's journals for proof.

But, being specific about your room:
If you want a good baseline, a decent 600w HPS bulb with a decent reflector provides effective coverage for 1mx1m of horizontal grow canopy, and can effectively penetrate to just under 1m depth, obviously that's without any leaves in the way...

But you got bigger concerns than what bulbs to buy fella..
No air exchange????? Forget it...

In my humble opinion, the top 10 most critical things needed for growing in order of importance are (drumroll please..) : Joint 1,2,3,4,5,6,7,8 and 9 are plenty of light and loads of air exchange. 10th is nutes, system, additives, etc...

rocky81426

I agree. HPS put off alot of heat..and plants need CO2 to live and flourish

Xgone.

...moved to lighting...

kbean

uhm so your saying that a 1000wer ja 2x600wers would get that room temp too high with a closed door thats opened say for 1 hour a day?
There is nowhere to vent, its just a room with a window and a door. Cant open the window cos its -10c outside, couldnt build such a vent that went through glass.At the moment I have one 250w in the room and that did absolutely nothing to the room temp, totally the same as in everywhere else in the house.

DarkFox

I'm not talking about temperatures kbean, just 'cause your room temps are ok it doesn't mean your plants will grow well. If you were in an air-tight room with no oxygen would you be happy just 'cause the temperature was a nice 21 degrees C.?

Maybe in a real large room you could grow one small plant under flouros or an envirolite or something, but you're gonna really try and grow 12 plants under HPS without proper air exchange....?!?

There's loads of info on here already about air and ventilation so all I'm gonna say is the minimum needed for growing decent weed is a complete change of your grow room air volume every 5 minutes. Pro growers aim for complete changes every minute.

kbean

riight, so, in my case co2 would be musthave?

Ripcord

Please elaborate. HPS vs MH? Here we go again.....If your trying to say HPS puts off more heat per watt.......

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