Lighting Quesion - HID + CFL = ?

docarzt

Member
Hello! I have just set up a 6' x 6' grow closet with the following lights:

2 65w CFL @ 2700k
1 125w CFL @ 6400k
1 400w MH

I have the 2 65's stationed just above the top of my planters on the right and the left, with the MH overhead.

My question is where should I station the 125? The package says it is equivalent to a 400w, so I'm thinking it should go next to the MH in its own reflector, but honestly there is no room.

Also, a related question: when mixing CFL and MH, do I add the wattage together to determine the total light exposure? Since the 65's are supposedly equal to 300w and the 125 is equal to 400 (?), is my setup equivalent to 1400w/combined lumens of all the light?
 

minibotwin

Active Member
The packaging should have the lumens label on it.. Basically look at how much you've got combined. Then figure out your sq footage. & it's not always about the lumens itself as it is the color spectrum... On one of my threads there's a GREAT chart the helps, I'll try to get it & post it here for you.
I'd go w/ the MH on top, then make sort of a triangle around the plants with the CFLs. Put the 2 smaller ones a little closer together with greater distance between those & the larger CFL.
 

minibotwin

Active Member

The high points on this chart indicate the activity of chlorophyll in your plant (meaning the growth) This chart basically indicated you need the certain spectrum for certain results.
 

docarzt

Member
Oh, thanks. That is awesome info. So it turns out I have around 8800 lumen per square foot, which is way over what most grow faqs call for but the heat is under control (around 78 degrees with 30-35% humidity) and I'm assuming that is the only concern with overlighting... ?
 

minibotwin

Active Member
You can almost never do too much lighting indoors... As indoor lighting will never compare to what the sun provides. You could probably get rid of one of the CFLs for now if you're concerned.
But yes, heat-therefore humidity levels, etc, are one of the main concerns for overlighting.
Do you know what KIND of CFLs they are? Daylight? Soft white? Cool white? etc... That usually makes a difference! Try to stay away from any Cool Whites, etc.. With CFLs, Daylight is your best bet!
I know it takes a lot to get the whole light thing figured out... I got lost in all the research I did, but that chart was the clearest info I had ever found!
 

docarzt

Member
You can almost never do too much lighting indoors... As indoor lighting will never compare to what the sun provides. You could probably get rid of one of the CFLs for now if you're concerned.
But yes, heat-therefore humidity levels, etc, are one of the main concerns for overlighting.
Do you know what KIND of CFLs they are? Daylight? Soft white? Cool white? etc... That usually makes a difference! Try to stay away from any Cool Whites, etc.. With CFLs, Daylight is your best bet!
I know it takes a lot to get the whole light thing figured out... I got lost in all the research I did, but that chart was the clearest info I had ever found!
Ah, well this is what I'm using for 65w cfl:

http://www.lowes.com/pd_46931-75774-L65TN_0_?productId=3197521&Ntt=65%20watt&Ntk=i_products&Ns=p_product_price|0&pl=1&currentURL=/pl__0__s?newSearch=true$Ntt=65%20watt$y=10$x=32


Which is listed as a soft white. It says that the color spectrum is 2700k. Should I ditch them?
 

White Noise

Member
Don't ditch them, soft white is the spectrum you want for flowering. Also keep in mind that wattage comparisons on those CFLs aren't compared to HID lights, but to incandescents. Therefore a 125w CFL does not = a 400w MH, it would equal a 400w incandescent.
 

docarzt

Member
Ah thanks for the clarification! I guess the moral of this story is.... "it's spectrum, and lumens, stupid!"
 
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