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400 watt hps;good enough?

  • by 707706ca2ga
  • Dec 23 2010 03:13 AM
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  • THE BOTANIST

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Posted 23 December 2010 - 03:13 AM

Ive got 5 plants in a small space 1 400 watt hps w/ mylar on 3 walls is that enough light or should i go get a extra 150 watt hps for supplemental lighting
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  • vertical grower

  • wert7676
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Posted 23 December 2010 - 09:29 AM

you need 50-75 watts per square foot. 400/50=8 sq ft 400/75=5.3. but the standard would be a 2.5x2.5 foot space for a 400.

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  • GrapeStreet
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Posted 23 December 2010 - 12:49 PM

Also depends on the "canopy size" of your plants, and the "canopy density" as well. If you've got a stubby indica (which Kushs generally are) Then you'll need more light for penetration of the dense bush than you would if you had a spindly sativa in the same space.


"Is ___ enough?" is too general. Sure, 400w is enough, but the more the better, and your plant's shape and size will change things as well. The more light you've got, the more growth can occur, given other necessary environmental conditions are being balanced as well.

And Wert's right on with the calculations. While you can run a space almost 3x the size of his recommended space, if you only use 2.5x2.5 for a 400w you'll be sure to maximize the lighting requirements for the space, rather than coming up short or just enough.

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  • motorheed
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Posted 23 December 2010 - 01:51 PM

yeh all good points but mind heat issues which an extra 150 watts could bring you;)

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Posted 23 December 2010 - 04:09 PM

yeh all good points but mind heat issues which an extra 150 watts could bring you;)



If hes doin a good job of venting the 400 W HPS heat than I doubt the 150 W HPS is gonna make a difference. I have a both 400 HPS and 150 HPS and the smaller one puts out hardly any heat. Might as well be a CFL...haha....

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  • lotuselise
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Posted 23 December 2010 - 08:48 PM

i got a 5 by 4 by 8ft room and my 400w light is more than enough.

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Posted 23 December 2010 - 09:08 PM

has anyone ever had a bulb making a funny sound its not the ballast its a digital so it makes almost no noise just the little fan but my bulb was making a high pitch sound ,i need to go pick up a extra incase it goes out i just switched to 12/12 and i dont want any stress

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Posted 24 December 2010 - 03:10 AM

i got a 5 by 4 by 8ft room and my 400w light is more than enough.



How many plants do you have in there?

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Posted 24 December 2010 - 05:04 AM

4, you can check out pics of my room in my grow journal below in my sig

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Posted 24 December 2010 - 01:54 PM

although at this time it's not cost effective, a light mover would probably be a way to make that 400w more effective in a bigger space.

personally, I have a 400w HPS and my glow tray size is 2.5' x 4' and I couldn't get more than 2 good size plants in there. but that's because they're bushy:hello:

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  • motorheed
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Posted 24 December 2010 - 02:25 PM

If hes doin a good job of venting the 400 W HPS heat than I doubt the 150 W HPS is gonna make a difference. I have a both 400 HPS and 150 HPS and the smaller one puts out hardly any heat. Might as well be a CFL...haha....


you,d be surprised bud,even if his venting is good for a 400 watt hps how much extra heat a 150 watt puts out,but as you say i hope its not an issue

peace........................:smoking:




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