What happens to Spectrum when we dim our lights?

Rocket Soul said:
Cmh with led would be ace but that would mean another 20 lights on top of new leds as were not talking about a couple of tents. Also means dialing everything in which is time which is even more money. But im thankfull for any advice :)
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My bad did not understand the scope of the project.
 
No worries. Its a huge difference growing big multi m2 cannopies to smaller grows. Also around here for comercial the margins are very thin, 3€ per gram for top buds is hard to make a living off. Lucky i only grow for smoke and kicks
 
jonsnow399 said:
everyone is interested in cobs, but i was wondering about gavita's 750 watt de bulb dimming. The website says it can be dimmed to 400 watts. I emailed the rep and asked him how did it affect spectrum, efficiency and lamp life. I will let you know what he or she says when they reply.
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Gavita's do change spectrum visibly when you dim them. The HPS light does turn noticeably more blue if you dim them more than just a bit.

Forgot what it was exactly, but I could even quantify this somewhat when post processing photo's. The color temperature (white balance) was higher on the photo's taken under dimmed light. Probably even a smartphone can see this nowadays.
 
that should be the same for any de hps. i have some (idle) ushio pro plus bulbs on solistek matrix i think they dim as low as 600. ill try to shoot 1100W vs 600W with the spectrometer next time im over there
 
Rocket Soul said:
Hey Ttystikk
Do you still have that paper or a link? Im looking at leds for a friends grow, trying to figure out some kind of hybrid hps led setup. His problem is that wintertime is so cold that any watts saved by led gets eaten up by having to put loads of extra heating, and summer is too hot (no aircon, only ventilation). Looking into a setup where he could use as much dimmed hps he needs for heating the cannopy and Qbs to fill in the the missing light. But if the HPS gets dodgy when dimmed down it might be a bad idea. Would really like to get my hands on that paper.
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Google Philips lighting and the specific lamp.

You need insulation!
 
Ushio pro plus at 600 and 1100W. i tried to do 1100 at a slightly greater distance to get the light intensity equal

looks like only a very slight spectrum shift if any
 

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Not dimming but since this thread is cobs and spectrum, What is the difference between the Citizen 6500K 80CRI spectrum and something like a Cree 4000K that allows the Citizen to grow a much more naturally formed head of lettuce and also better structured cannabis plant?
Something in the blue/red ration, red/far red?
@CobKits ?
 
OneHitDone said:
Not dimming but since this thread is cobs and spectrum, What is the difference between the Citizen 6500K 80CRI spectrum and something like a Cree 4000K that allows the Citizen to grow a much more naturally formed head of lettuce and also better structured cannabis plant?
Something in the blue/red ration, red/far red?
@CobKits ?
Click to expand...
@Stephenj37826 ?
 
ttystikk said:
Google Philips lighting and the specific lamp.

You need insulation!
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Thx, found some info. In this specific grow insulation isnt really an option; wintertime the cold is from venting air from the outside, and sealing the room, w aircon is a bad option due to the attention it draws. May look into near-infrared heating lamps aswell.
 
CobKits said:
Ushio pro plus at 600 and 1100W. i tried to do 1100 at a slightly greater distance to get the light intensity equal

looks like only a very slight spectrum shift if any
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Kudos to you Cobby, that's what we need, testing instead of speculation. Does the 600 run the same lumens or par per watt as 1100?
 
OneHitDone said:
Not dimming but since this thread is cobs and spectrum, What is the difference between the Citizen 6500K 80CRI spectrum and something like a Cree 4000K that allows the Citizen to grow a much more naturally formed head of lettuce and also better structured cannabis plant?
Something in the blue/red ration, red/far red?
@CobKits ?
Click to expand...
the only difference between a 6500k 80 cri and 4000k 80 cri cob is thickness of phosphor layer.
 
CobKits said:
yes the thickness of phosphor layer makes a different spectrum

absorbs the narrow band blue light into more of the wide band yellow/orange/red
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Maybe I should have been more clear....
Why does the Citizen 6500K spectrum produce plants like this:
img_20170603_131355-jpg.3954063


When Vero, Cree, etc in 4000K produce very unnatural growth like this?
img_5877-jpg.4000339
 
Maybe the ratio of far red and deep red is different?I dunno i am guessing here, i know one makes them stretchy and the other is more focused on developing the roots so plants stay shorter...should check where the red peaks for citi 6500 and cree and veros 4000 and compare if there is any significant difference that is maybe the reason why the plants act like that
 
OneHitDone said:
Maybe I should have been more clear....
Why does the Citizen 6500K spectrum produce plants like this:
img_20170603_131355-jpg.3954063


When Vero, Cree, etc in 4000K produce very unnatural growth like this?
img_5877-jpg.4000339
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Spectrum is not the only difference between these setups: 4000k is sitting on its own where 6500k is more packed. Packed plants seems to stretch a bit more to avoid shade especially if they are touching. The 6500k looks like some bushy plants with some parts of it stretching to get out of shade or touching branches of other plants. Have you tried what happens if you only vegg 1 plant in your 6500k area? Does it get the same structure or is super bushy like the 4000k plant?
IMHO, YMMV etc etc.
Also higher k spectrums are good for leafy greens, there was a thread about it some time back and the 3500k grew some freakish ugly lettuce. All plants dont like the same spectrum ;)

Btw the 6500ks look lovely
 
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