Can you just add up the amount of light?

JuicyyFruit

JuicyyFruit

Member
I have 4-5 lights for one plant right now. Four of them are 23 watt (100w equivalent) CFLs with a brightness of 1600 lumens and light appearance at 5000k. The fifth light is a 30 watt LED with a brightness of 1600 lumens and light appearance at 6500k.

Can I add that my plant is getting a total of 99 watts, 8000 lumens, at a light appearance at 5000 and 6500 k?

If so is that enough for one plant throughout its vegetation?

Or is there another factor you have to look at?
 
Nullis

Nullis

Moderator
The inverse square law pertains to light\distance and yes it decreases exponentially the further from the source it gets.

It doesn't have to be that complicated if you just want to determine watts per m², add them. CFL's are a different situation anyways though because there is no one fixed light source. Even a single CFL due to the shape of the bulb isn't really a 'point source' of light.
 
B166ER420

B166ER420

Well-Known Member
Nullis said:
Even a single CFL due to the shape of the bulb isn't really a 'point source' of light.
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But it is reasonable to say that with more than one cfl spread out that there would be multiple point sources of light....just saying.Therefore it's always better to have multiple point sources of light spread around a plant...ie 4-23w bulbs would be better than 1-100w bulb.
 
greasemonkeymann

greasemonkeymann

Well-Known Member
B166ER420 said:
But it is reasonable to say that with more than one cfl spread out that there would be multiple point sources of light....just saying.Therefore it's always better to have multiple point sources of light spread around a plant...ie 4-23w bulbs would be better than 1-100w bulb.
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careful with that logic though, it can misled you, for instance four 250w HIDs will NOT be better than a single 1000w HID.
 
B166ER420

B166ER420

Well-Known Member
greasemonkeymann said:
careful with that logic though, it can misled you, for instance four 250w HIDs will NOT be better than a single 1000w HID.
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I was clearly speaking of compact fluorescent light...saying 4-23w
greasemonkeymann said:
you are confused, 2700 k is the spectrum, not the amount of lumens.
and, he doesn't want a 2700k during flowering, wrong spectrum
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I know it is .....veg cycle thrives under a light spectrum that mimics summer and spring,6400k or 5000k ,while flower cycle thrives with a fall 2700k red .
 
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OGkushNC

OGkushNC

Well-Known Member
I vegged a couple monster plants under a 100w mh 8500 lumens 6500k and added a couple of cfl's 1600 lumens 6500k!. add some more as long as you have the equipment to cool the area. Also meant to mention I'm still in the process of growing these plants under the exact same lights. However, my flower room consist of a single 400w mh/hps and a 100w hps. Its all in the grower and I've come to realize the more I grow so happy growin man!
 
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A

az2000

Well-Known Member
JuicyyFruit said:
I have 4-5 lights for one plant right now. Four of them are 23 watt (100w equivalent) CFLs with a brightness of 1600 lumens and light appearance at 5000k. The fifth light is a 30 watt LED with a brightness of 1600 lumens and light appearance at 6500k.
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You have a total of 122w actual, and an average color temperature of 5300k.

If your plant is in a 2x2' space, that's 30.5w/sq ft. That's ok for early and mid veg. Going into flower you'll want 40w/sq ft. Late in flower you'll want 50w/sq ft. In flower you'll want warmer light too.

Lumens is the amount of light emitted by a source. I don't know why they wouldn't add up. But, it's kind of a pointless number because a large amount of the light will emit in directions other than where the plant is. If you use a reflector to concentrate the light, that's not 100% efficient. (Compare a 20w CFL bulb's packaging to a 20w spot or flood with an internal reflector. The lumens of the later will be lower because 60% or so of the lumens are being reflected). A better measurement is lux, the amount of lumens falling on a surface. There are free lux meters for smartphones. I have "BeeCam Light Meter." There may be better ones.

Personally, I would go with LED instead of CFL. You don't have to worry about burning the plant if they touch, etc. Home Depot sells Cree A19 an BR13. They cost more but you get a 10 year warranty honored by HD (walk in and replace the bulb.). See here (<<link) for more info. Some people are using these inexpensive ones from China. (<<link, be sure to get the e27 base unless you're doing something creative.).
 
JuicyyFruit

JuicyyFruit

Member
az2000 said:
You have a total of 122w actual, and an average color temperature of 5300k.

If your plant is in a 2x2' space, that's 30.5w/sq ft. That's ok for early and mid veg. Going into flower you'll want 40w/sq ft. Late in flower you'll want 50w/sq ft. In flower you'll want warmer light too.

Lumens is the amount of light emitted by a source. I don't know why they wouldn't add up. But, it's kind of a pointless number because a large amount of the light will emit in directions other than where the plant is. If you use a reflector to concentrate the light, that's not 100% efficient. (Compare a 20w CFL bulb's packaging to a 20w spot or flood with an internal reflector. The lumens of the later will be lower because 60% or so of the lumens are being reflected). A better measurement is lux, the amount of lumens falling on a surface. There are free lux meters for smartphones. I have "BeeCam Light Meter." There may be better ones.

Personally, I would go with LED instead of CFL. You don't have to worry about burning the plant if they touch, etc. Home Depot sells Cree A19 an BR13. They cost more but you get a 10 year warranty honored by HD (walk in and replace the bulb.). See here (<<link) for more info. Some people are using these inexpensive ones from China. (<<link, be sure to get the e27 base unless you're doing something creative.).
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Thanks a lot for your time and info.
 
Ace Yonder

Ace Yonder

Well-Known Member
az2000 said:
Some people are using these inexpensive ones from China. (<<link, be sure to get the e27 base unless you're doing something creative.).
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I don't know much about e27 base leds, but at first glance if I was going for the corn-cob style I would probably go with something with 3w chips (Like these http://www.ebay.com/itm/E27-69W-23X3W-High-Power-LED-Chips-RED-BLUE-Corn-Grow-Light-Hydro-Plant-Veg-Lamp-/261642125533?pt=US_Hydroponics&hash=item3ceb1600dd) instead of those ones with the little SMD chips for the added intensity and penetration, but I could be wrong.
 
Ace Yonder

Ace Yonder

Well-Known Member
JuicyyFruit said:
I have 4-5 lights for one plant right now. Four of them are 23 watt (100w equivalent) CFLs with a brightness of 1600 lumens and light appearance at 5000k. The fifth light is a 30 watt LED with a brightness of 1600 lumens and light appearance at 6500k.

Can I add that my plant is getting a total of 99 watts, 8000 lumens, at a light appearance at 5000 and 6500 k?

If so is that enough for one plant throughout its vegetation?

Or is there another factor you have to look at?
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Depending on certain factors, yes.
For example, I have these little cheapo 12w "COB" (I doubt they are actually cobs, but that's how they are marketed) LED bulbs (also e27 base).
DSC01826.JPG DSC01827.JPG

At 12" from the lights (Actually closer to 11" since the actual meter is about 1" thick), you can see how the light pretty much adds straight up (Two lights wind up giving off 186% as much lux as one light does). Over a larger area, it probably would have a more noticeable difference between one big light and multiple smaller lights since a single big light has a longer range before the intensity falls off.
DSC01823.JPG

Lux meter zeroed out with both lights off, showing no ambient light inside the box (Don't want to contaminate test)
DSC01820.JPG

One light clicked on = 5,460 LUX
DSC01821.JPG

Both lights clicked on = 10,150 LUX
DSC01822.JPG

So, the LUX from the 2 lights add up to 186% of the LUX from one of the lights. So they add up with a slight loss that should increase the farther from the lights you get, but with the multiple lights all placed close to the plant you may actually wind up with MORE light hitting the plant than from one stronger but more distant light source.
 
Ace Yonder

Ace Yonder

Well-Known Member
greasemonkeymann said:
you are confused, 2700 k is the spectrum, not the amount of lumens.
and, he doesn't want a 2700k during flowering, wrong spectrum
Click to expand...
Actually if he is going to be flowering with CFL then 2700K IS the correct spectrum. With K color temps, lower is redder and higher is bluer, and since you want more red during flower 2700K is the way to go. You may want to keep a few 6500K for the extra UV-B, but the effect might be negligible.
 
A

az2000

Well-Known Member
Ace Yonder said:
I don't know much about e27 base leds, but at first glance if I was going for the corn-cob style I would probably go with something with 3w chips (Like these http://www.ebay.com/itm/E27-69W-23X3W-High-Power-LED-Chips-RED-BLUE-Corn-Grow-Light-Hydro-Plant-Veg-Lamp-/261642125533?pt=US_Hydroponics&hash=item3ceb1600dd) instead of those ones with the little SMD chips for the added intensity and penetration, but I could be wrong.
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It's more involved than just wattage of the diode. For example, lumens per watt is important. Also, whether the light is full-spectrum white or "blurple." Whether the chips are Epi(whatever) or a more respected brand.

The AliExpress bulbs I linked to are Cree, produce 107 to 125 lumens per watt, and are white (3000k or 6250k). What you linked to is Epistar, no mention of lumens, and are red/blue spectrum.

I haven't used them yet. I'm going from specs on the AliExpress site. Someone experienced with LEDs does use them. It's being discussed a little here. (<<link).

I use Cree A19 and BR30 from Home Depot. The A19 9.5w produces 84 lumens / watt. They come with a rubbery protective coating on the glass globe. This reduces intensity by 10%. It's advised to remove it. So, let's say it's 92 lumens / watt. (It has a frosted globe which probably reduces lumens a bit too.). So, in theory, these AliExpress bulbs sound good. People have (and may still do) grow entirely with the A19s, not merely as supplements. If the quality of white is similar and the lumens/watt are better, they should be better than the Epistar bulb you linked to. ("Better" if you're ok with a larger number of softer sources of light. The one you linked to may be stronger and require fewer bulbs. But, that's not necessarily "better" in other ways, such as the watts used to produce lumens, or reduced coverage.).
 
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