Graytail's 4th Perpetual: 4x4 Samsung Panels

While we're on the subject of lighting, I can share some rules of thumb.

You want 1200 umols at the top of the canopy and 500 at the bottom - that's "perfect".

In a 4x4, with Samsung diodes, you need 120,000 lumens to get 1200 umols. That will provide a 2 foot effective canopy. Other light sources will require higher lumens because of the PAR differences.

A 1000DE hps delivers 140 lumens/watt. Single ended hps are 130 Lu/W. CMH has a great spectrum but it only gets 115 Lu/W. COBs and Samsungs run at 150-200 Lu/W depending on how hard you drive them. My setup is nominally over 190, and I lose 7-8% in drivers, etc, so I get 170+ at the wall.

Let's see if I can format this in a way we can read it ...

..................Lux/ppfd....Lu/W.....factor
Grolux floro .......34 .......30 .......0.87
sunlight ..............54
blurple ...............55 ......110 ......2.01
CMH Agro ..........59 ......100 ......1.70
CMH ...................65 ......115 ......1.77
LM561c ..............66 ......180 ......2.72
Cree3590 ...........66 ......170 ......2.55
MH .....................71 ......110 ......1.55
Fluoro(cool white) 74 ....65 ......0.88
1000DE .............77 .......140 ......1.82
600HPS .............82 .......130 ......1.59

:)
 
Excellent Gray

I’m retaining just a little bit more of the technical side of things every time I read stuff about it. That was super helpful, thanks.

On the shadowing thing - something that’s amazed me, which I now understand, is the lack of any discernible shadow when I pass my hand (or camera) under the light/over the plant. Like you say, it’s like the light comes from everywhere.

Do those light (ppfd) measuring apps you can get for iPhone work, does anyone know?
 
Amy Gardner said:
Excellent Gray

I’m retaining just a little bit more of the technical side of things every time I read stuff about it. That was super helpful, thanks.

On the shadowing thing - something that’s amazed me, which I now understand, is the lack of any discernible shadow when I pass my hand (or camera) under the light/over the plant. Like you say, it’s like the light comes from everywhere.

Do those light (ppfd) measuring apps you can get for iPhone work, does anyone know?
Click to expand...
They measure just lumens. At least the two that I have on my phone anyways. I haven't found any that measure ppfd yet....and I am too cheap to buy a meter LOL.
 
:p:cool: Cheers @Derbybud It is looking pretty great that’s for sure. :)

Am kinda curious that’s all, so I thought if it was that easy. Lumens won’t really tell me anything about what the plant is getting - will it.
 
Actually, if you can get accurate lumen readings, that should be as good as the real thing. The relationships are the same, no matter the measure. Half is half, etc. And we know the PAR ratio for the LM561c diode spectrum, so we can convert to PAR umols. You can measure at 2 feet in the middle, at the walls, in the corners, etc. You can do the same for 500mm headroom, 400mm ... etc ... top of the canopy, bottom of the canopy ... dial it right in!

I'm surprised I never thought of it before. Thanks!

:thumb:
 
Oh - that’s great! :thumb: this’ll be fun
Have a great Sunday :rollit:
 
You're perfectly welcome! We Brixers have to keep track of each other. :passitleft:
 
mornin Gray.....:passitleft:
 
Hey Gray, Duggan! :passitleft:Mmmmm. :passitleft:
 
:passitleft:
 
Boy am I glad I wander this neighborhood. Graytail, that was excellent reading material. :hugs: I just love the way he explains it. Like Amy, I’m beginning to retain more and more with every reading.

The qb over my Zam x Pan is what’s making the biggest difference, and may be my salvation with the impending tear down. Thank goodness Dan loves me. Lol!
 
dec·a·dence
ˈdekədəns/

It struck me that I have now expanded the 4 part tray into an 8 part tray. From top to bottom, left to right, I'm currently enjoying ...:

Bubba Hash
Purple Orange CBD
DC Purple
Zam+
Carnival
GT Haze
and Malawi

:slide::bongrip:

Decadence

Decadence

  • Media owner Graytail
  • Date added

:p
 
..."Spice of life", as they say...cheerz...h00k...:rollit::passitleft:
 
Very cool tray! She has nice curves....:ganjamon:
 
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