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OfflineAtolas
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Registered: 08/08/12
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400 watt in small space?
    #634547 - 08/11/12 05:26 PM (4 years, 3 months ago)

Would it be safe if i installed a 400 Watt HPS setup into a small (2-3' height) box?


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Offlinecharlymanson
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Re: 400 watt in small space? [Re: Atolas]
    #634565 - 08/11/12 10:58 PM (4 years, 3 months ago)

Your plants will grow way too tall with that light, I actually have a 6 foot enclosure with a 400 watt and
they are outgrowing that! lol next time I have to veg less. You may be able to with a auto flower or
something you flower from day 1 but I have no experience with that so don't take it from me as I am on my first grow to.


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OfflineAtolas
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Re: 400 watt in small space? [Re: Atolas]
    #634571 - 08/11/12 11:52 PM (4 years, 3 months ago)

yes i am using Auto flowering, im not concerned for the height just the safety. I dont want my box overheating and catching into flame if you know what i mean :wink:


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InvisibleStonethM
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Re: 400 watt in small space? [Re: Atolas]
    #634573 - 08/11/12 11:55 PM (4 years, 3 months ago)

It's do able.
But you're going to need a shit ton of ventilation.
Probably be easier to maintain with a 250 watt.


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Offlinesidetwist
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Re: 400 watt in small space? [Re: charlymanson]
    #634601 - 08/12/12 06:29 AM (4 years, 3 months ago)

Quote:

charlymanson said:
Your plants will grow way too tall with that light, I actually have a 6 foot enclosure with a 400 watt and
they are outgrowing that! lol next time I have to veg less. You may be able to with a auto flower or
something you flower from day 1 but I have no experience with that so don't take it from me as I am on my first grow to.



Some strains grow taller than others, and also how you train them is important for this question. You know normally the apical bud grows directly towards the sun and suppresses the side branches through the Auxin hormon. When you LST or top them early on you'll see more bushy behaviour because the plant thinks she will have better chances to get pollinated when she sends the side branches up. This spreads the growth of early flower stage(which can be massive, like 200%) betweenmore than one cola.

First the white pistils come out and get more and more and at a certain point the calyxes at the foot of the pistils start really growing, the plant almost ceases height growth (unless you have a crazy sativa) and concentrates on budding (=>reproduction).

But no matter what OP does, three foot are a bit small for 400W HPS to burn down on your plants directly. The immense radiation and heat will produce a high mineral flow to the upper plant parts which will burn them.
Even with a 150W HPS setup (not to speak of 400W), the plants should veg only in the lower quarter of the cabinet, when they start to flower they will stretch some weeks until the calyxes really start "swelling", then you should still be able to navigate the light higher or lower to avoid burning, means minimum the upper quarter of the closet belongs to the lights. The lower one must belong to the plant including the pot and the lower middle is for stretching, the upper middle is safety zone towards the light.


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Live slow, die old.


Edited by sidetwist (08/12/12 06:30 AM)


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OfflineBudGrower
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Re: 400 watt in small space? [Re: sidetwist]
    #634623 - 08/12/12 01:06 PM (4 years, 3 months ago)

I have grown in cabinets of this size for 10 years. The lighting has evolved. For a beginning point I looked to natural systems. The highest solar output is at the equator, no plant on earth could evolve to use more than this amount of light. My goal was to approach that Lumin output in the CAB. I don't recall the numbers but ultimately a 250 HPS light produced something approaching equatorial solar output in the CAB.

The 250 HPS produced remarkable results 4-4.5 oz per grow cycle! These CABs are done as a SCROG. SOG could work but SCROG training seems less hassle. As Sidetwist states you will have to train them in someway, natural untrained growth will quickly outgrow this space.

The 250 HPS produces a huge amount of heat that can be managed in this small of space with aggressive ventilation. There are some caveats. If there is any problem in the ventilation you will kill the plant in the Cab I think it takes less than an hour with the heat. You could avoid the fire hazard by using metal for the CAB. Mine are wood and ultimately the fire hazard compelled me to move to CFL lights. The CFL's greatly reduced the problems with HPS but you still had to deal with them.

Where I am now is 8 21" T5 ho 6500k 96 watts total. Heat is not an issue. To burn the plants they must physically touch the lamps. My production per cycle is at 3.5- 4 oz down from the HPS but the trade is well worth it. Safety does have a price and the hassle and headache is way down too. My biggest grow worry is once again the Feds, as it should b ewith our fucked up political system.

I have just recently (last 2 motnhs) started growing in larger tents with LED lights. I do not think LED light will work in the small CABs. LED lights appear to burn the plants without 15-20" of headroom above the plants.

This has been my experience and I am quite happy with compromise in this setup. It is a predictable trouble free system.

Good luck with your grow!

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Offlinephrostbyte
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Re: 400 watt in small space? [Re: BudGrower]
    #634695 - 08/13/12 01:47 PM (4 years, 3 months ago)

For something so small I would use a 90W or more LED Ufo.  they work very well for smaller spaces and produce almost no heat at all.  Not to mention use hardly any electricity at all.  I would say a 400w light is far too much heat for such a small space.  It would be dangerous IMO.


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Offlinesidetwist
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Re: 400 watt in small space? [Re: BudGrower]
    #634711 - 08/13/12 02:41 PM (4 years, 3 months ago)

Quote:

BudGrower said:

Where I am now is 8 21" T5 ho 6500k 96 watts total. Heat is not an issue. To burn the plants they must physically touch the lamps. My production per cycle is at 3.5- 4 oz down from the HPS but the trade is well worth it. Safety does have a price and the hassle and headache is way down too. My biggest grow worry is once again the Feds, as it should b ewith our fucked up political system.

Bg




Nice stuff man.


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Live slow, die old.


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