What happens to Spectrum when we dim our lights?

[Evil-Mobo]

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

My bad did not understand the scope of the project.

 

[Rocket Soul]

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

 

[wietefras]

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.

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.

 

[CobKits]

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

 

[ttystikk]

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.

Google Philips lighting and the specific lamp.

You need insulation!

 

[CobKits]

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

 

[ttystikk]

Mix COB's with 315 CMH if that's what youre after IMHO.

I know @GroErr has done this in the past and I think @ttystikk as well.

Never mixed HID with LED, except a tiny blurple UFO many years ago. Didn't do shit lol

 

[OneHitDone]

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 ?

 

[ttystikk]

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 ?

@Stephenj37826 ?

 

[Rocket Soul]

Google Philips lighting and the specific lamp.

You need insulation!

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.

 

[jonsnow399]

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

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?

 

[CobKits]

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 ?

the only difference between a 6500k 80 cri and 4000k 80 cri cob is thickness of phosphor layer.

 

[OneHitDone]

the only difference between a 6500k 80 cri and 4000k 80 cri cob is thickness of phosphor layer.

So there is no spectral output difference?

 

[CobKits]

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

 

[CobKits]

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?

i dunno

 

[OneHitDone]

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

Maybe I should have been more clear....
Why does the Citizen 6500K spectrum produce plants like this:

When Vero, Cree, etc in 4000K produce very unnatural growth like this?

 

[The Dawg]

Damn I'm Busting A Gut Here. I Know Exactly What Happens To The Spectrum When Its Dimmed.

It Gets Dimmer Ho No He Didn't But Yes He Did Bada Bing See Yall Next Week At The Fillmore

 

[CobKits]

because 6500k and 4000k are completely different spectrums? 6500k has a lot more blue

 

[waynejohn]

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

 

[Rocket Soul]

Maybe I should have been more clear....
Why does the Citizen 6500K spectrum produce plants like this:

When Vero, Cree, etc in 4000K produce very unnatural growth like this?

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