Great post from another site
Great post from another site
by NoFucks2Give
SPYDRx is a much better framework than the CoBs (comparing to a competing CoB only panel). CoB put out too much power and are spaced to far apart. This puts limits on how close you can get to the canopy.
Fuck Watts. Watts don't mean shit. BTW: No such thing as PAR Watts. PAR is quantum µMoles, no Watts, watts would be Radiometric not Quantum.
RE: PPFD @ 54" x 54" = 1200 PPFD @ 60" x 60" = 900. PPFD is height sensitive, height needs to be specified or it don't count. Area is okay, but without height it means nothing.
If the PPFD is measured at 1 meter then the numbers are very good. Except due to the nature of CoBs the uniformity may be shit. It's good that the CoBs are equal distance to each other, but uniformity will be very height sensitive. Depending on the Radiation Distribution Curve The height should be a multiple of of the distance between CoBs.
If the PPFD of the SPYDRx and the CoB's are anywhere in the same ballpark (at the same height), SPYDRx is the way to go, hands down.
The height above the canopy is a huge factor. PFFD should be measured at 1 meter. Some sellers prefer to specify less. e.g Heliospectra specifies 18" and they recommend they be hung at 18" over the canopy. The SPYDRx having the LEDs spread out where Heliospectra photons are projected from a smaller area has teh 18" limitation and SPYDRx does not.
AT 18" the PPFD is 4.8 times what it would be at 1 meter. The closer you can get to the canopy is of quantum importance.
As the fixture gets closer to the canopy the PPFD rises exponentially with the Inverse Squares Law.
12" = 10.8x
11" = 12.8x
10" = 15.5x
9" = 19.1x
...
4" = 96.9x more flux to the canopy than a fixture at 1 meter.
Another important issue is the wavelengths. With CoBs you are stuck with white. BLM (Fluence) will give you what you need. (edit as do Amares)
While the stoners on this site have a shitload of anecdotal evidence supporting broad spectrum, it is just that anecdotal.
Every recent scientific study has found narrow band wavelengths superior to broad spectrum. Look at the huge vertical farms that were started on big budgets. These guys have the incentive and the budget to do things right. They hire the experts that know the scientific research. You will not find one big budget vertical farm using white (edit" white only) in the growth stage.
There is a lot of moaning on this site from the CoB snobs about how narrow bandwidth LED fixtures don't stand up to their CoBs. That because their experience with narrow band fixtures is limited to the under $500 hucksters. The hucksters advertise how many 3 Watt Cree LEDs they have. Like I said Watts don't mean shit. What is much more important than the published wattage at 25°C is the temperature. Red and the other AlGaInP LEDs are very temperature sensitive. To the tune of losing 50% Radiant Flux by running the LEDs at 100°C. But they don't care they are selling their crap based on Watts.
Just because light bulbs were sold by Wattage does not mean LEDs can. Then the hucksters that sell by Wall Watts because they are too cheap to use efficient power supplies and LED drivers and the inefficiency drives up the Wall Watts. .It's the blind leading the blind out there.
Many of the stoners on this site are Blind. They always got the line "It works for me, look". Well GrowLux bulbs work pretty damn good too. But we van do better.
Unfortunately, cannabis being illegal at the Federal level and in most every country doing any significant horticulture LED research, there is no known light recipe or even a reliable Red:Blue ratio.
Stay the fuck away from UV and Far Red unless you know something I do not. In the few instances where they have been found to have a positive effect, it has been in a metabolism signaling scenario and for a very specific species. The hucksters spread misinformation based on their misinterpretation of these studies or worse they are just lying.
Too many of the stoners on this site are baffled by the bullshit and too and wouldn't see brilliance if it bit them in the ass.
Great post from another site
by NoFucks2Give
SPYDRx is a much better framework than the CoBs (comparing to a competing CoB only panel). CoB put out too much power and are spaced to far apart. This puts limits on how close you can get to the canopy.
Fuck Watts. Watts don't mean shit. BTW: No such thing as PAR Watts. PAR is quantum µMoles, no Watts, watts would be Radiometric not Quantum.
RE: PPFD @ 54" x 54" = 1200 PPFD @ 60" x 60" = 900. PPFD is height sensitive, height needs to be specified or it don't count. Area is okay, but without height it means nothing.
If the PPFD is measured at 1 meter then the numbers are very good. Except due to the nature of CoBs the uniformity may be shit. It's good that the CoBs are equal distance to each other, but uniformity will be very height sensitive. Depending on the Radiation Distribution Curve The height should be a multiple of of the distance between CoBs.
If the PPFD of the SPYDRx and the CoB's are anywhere in the same ballpark (at the same height), SPYDRx is the way to go, hands down.
The height above the canopy is a huge factor. PFFD should be measured at 1 meter. Some sellers prefer to specify less. e.g Heliospectra specifies 18" and they recommend they be hung at 18" over the canopy. The SPYDRx having the LEDs spread out where Heliospectra photons are projected from a smaller area has teh 18" limitation and SPYDRx does not.
AT 18" the PPFD is 4.8 times what it would be at 1 meter. The closer you can get to the canopy is of quantum importance.
As the fixture gets closer to the canopy the PPFD rises exponentially with the Inverse Squares Law.
12" = 10.8x
11" = 12.8x
10" = 15.5x
9" = 19.1x
...
4" = 96.9x more flux to the canopy than a fixture at 1 meter.
Another important issue is the wavelengths. With CoBs you are stuck with white. BLM (Fluence) will give you what you need. (edit as do Amares)
While the stoners on this site have a shitload of anecdotal evidence supporting broad spectrum, it is just that anecdotal.
Every recent scientific study has found narrow band wavelengths superior to broad spectrum. Look at the huge vertical farms that were started on big budgets. These guys have the incentive and the budget to do things right. They hire the experts that know the scientific research. You will not find one big budget vertical farm using white (edit" white only) in the growth stage.
There is a lot of moaning on this site from the CoB snobs about how narrow bandwidth LED fixtures don't stand up to their CoBs. That because their experience with narrow band fixtures is limited to the under $500 hucksters. The hucksters advertise how many 3 Watt Cree LEDs they have. Like I said Watts don't mean shit. What is much more important than the published wattage at 25°C is the temperature. Red and the other AlGaInP LEDs are very temperature sensitive. To the tune of losing 50% Radiant Flux by running the LEDs at 100°C. But they don't care they are selling their crap based on Watts.
Just because light bulbs were sold by Wattage does not mean LEDs can. Then the hucksters that sell by Wall Watts because they are too cheap to use efficient power supplies and LED drivers and the inefficiency drives up the Wall Watts. .It's the blind leading the blind out there.
Many of the stoners on this site are Blind. They always got the line "It works for me, look". Well GrowLux bulbs work pretty damn good too. But we van do better.
Unfortunately, cannabis being illegal at the Federal level and in most every country doing any significant horticulture LED research, there is no known light recipe or even a reliable Red:Blue ratio.
Stay the fuck away from UV and Far Red unless you know something I do not. In the few instances where they have been found to have a positive effect, it has been in a metabolism signaling scenario and for a very specific species. The hucksters spread misinformation based on their misinterpretation of these studies or worse they are just lying.
Too many of the stoners on this site are baffled by the bullshit and too and wouldn't see brilliance if it bit them in the ass.
