Lighting Decisions are haaaard.

[organicnugz]

Posted this as part of an overall grow setup in another thread, but wanted to put this particular piece in here to see if anyone who has DIY vs pre-built experience would have some advice to offer. Have the know-how and the tools to do the DIY setup, so that's not an issue. Just didn't know if my logic was sound on how I want to setup the lights. This is in a Gorilla Grow Lite Line 4x4 for veg and 4x8 w/ 1' height extension for flower.

My options:
- 3x AC Infinity EVO6 500w bar light (1 veg, 2 flower), add UV/IR bars for flower
- 3x Mars Hydro FC-6500EVO 730w (1 veg, 2 flower), add UV/IR bars for flower
- For flower: Custom 10x CXB3590 PRO9 4000K 90CRI 72v @ 700-1400ma (probably 1400, dimmable to get some of that efficiency back) with 60deg. lenses. This gives a total wattage rating of somewhere around 500W @700ma, which I could turn up a bit, if needed. These will be on DIY bars, spaced evenly around the top perimeter of the tent (height of ~6.5-7ft), and only 6-12" from the wall of the tent. From there, I'd like to add in something akin to the Mars Hydro SP6500, Mammoth HighBay 630W Mint bar, or High Board 420 dual setup to run directly down the center of the area (looking for something more rectangular than square with 500w+, open to ideas), and give nice even light in the center of the tent. I'll run two (hopefully spectrum-controllable) UV/IR bars parallel with the long side of the tent. The idea behind this build would be that the COBs will be fixed at the top of the tent, and give high intensity beams of light to the ground for penetration, while the 301H/B diode light will be used for diffuse light in the center, in an attempt to alleviate hotspots and distribute light evenly across the entire canopy, including the edges of the tent where it seems no one gets great light. This would also allow me to place plants into flower and not have to move lights, as the plants should grow up into the 800-1000+umol area of the tent on their own. Just control the dimming, if required, to achieve results. I really like the new Samsung EVO chips, which are available on several lights. However, with the bar lights, it sounds like you need the lamps very close to the canopy to get the kind of light you need. I'd really like to get some of that hardcore COB beam action going on, and use the bar light style in the center, so there's plenty of penetration and well-dispersed light around the edges of the tent, as well as a central light providing even distribution across the center. For veg, I would either do a custom COB build and add supplements to it (say, 4-6 COBs (4000-5000k), with an HLG QB or similar fixture in the center), or one of the manufactured units with the EVO chips. Definitely interested in the EVO chips for veg, for sure, just dunno if flowering out autos will be worth the time to build out the COB array.

 

[1212ham]

I haven't heard CXB3590's mentioned in a long time.

Bars/strips or multiple boards are the way to go these days, I'm upgrading to GLA's High Light 420 strips. My old Bridgelux strips will be used for veg, side lighting and shop lights. If you feel the need for more light lower down, I'd add side lighting.

FWIW, I'd suggest starting with the 4x4 to gain experience, then expand. Experience has a way of changing opinions formed by research.

 

[tstick]

Those new Vivo Sun lights are looking really well-built and they always get rave reviews from the MIGRO channel.

 

[organicnugz]

I haven't heard CXB3590's mentioned in a long time.

Bars/strips or multiple boards are the way to go these days, I'm upgrading to GLA's High Light 420 strips. My old Bridgelux strips will be used for veg, side lighting and shop lights. If you feel the need for more light lower down, I'd add side lighting.

FWIW, I'd suggest starting with the 4x4 to gain experience, then expand. Experience has a way of changing opinions formed by research.

Yeah, they put out an upgraded version of the CXBs recently, giving 15% boost in efficacy at 90+ CRI, so you can get the same or better performance from the high CRI chips as you can with the lower CRI versions. I’ve seen that 4000k at 90+ CRI is very close to true sunlight spectrum, so I was hoping to bring that in. I had contemplated side lighting, but, back in the past everyone seemed to say side lighting wasn’t worth it. Of course, that was before the monster leaps in LEDs.

Do the bars/strips/boards have the penetration to flower anything deeper than 12” of canopy? My main issue is that I don’t see the point in growing a monster plant just to lollipop the bottom 50+% off of it, and spend all that time/energy on it. I do understand why we lollipop, and am definitely intending to, just would like to be able to flower say 2-3’+ of canopy on a 5’ plant. Maybe this is just a misconception from inexperience?

On the idea of a 4x4, can you expound? Like a single 4x4 for everything? Or one for each veg and flower?

 

[organicnugz]

Those new Vivo Sun lights are looking really well-built and they always get rave reviews from the MIGRO channel.

Bar lights I assume?

 

[tstick]

Bar lights I assume?

They have some bar lights I think. Just check out vivosun.com to see what they have.

 

[tstick]

Bar lights I assume?

Dude, my apologies! It IS NOT Vivosun that Migro likes....The brand is called "Vipar Spectra"....Anyway, my bad.

 

[organicnugz]

Dude, my apologies! It IS NOT Vivosun that Migro likes....The brand is called "Vipar Spectra"....Anyway, my bad.

gotcha. I’ve heard of them, I’ll take a look! Thanks!

 

[1212ham]

Yeah, they put out an upgraded version of the CXBs recently, giving 15% boost in efficacy at 90+ CRI, so you can get the same or better performance from the high CRI chips as you can with the lower CRI versions. I’ve seen that 4000k at 90+ CRI is very close to true sunlight spectrum, so I was hoping to bring that in. I had contemplated side lighting, but, back in the past everyone seemed to say side lighting wasn’t worth it. Of course, that was before the monster leaps in LEDs.

Do the bars/strips/boards have the penetration to flower anything deeper than 12” of canopy? My main issue is that I don’t see the point in growing a monster plant just to lollipop the bottom 50+% off of it, and spend all that time/energy on it. I do understand why we lollipop, and am definitely intending to, just would like to be able to flower say 2-3’+ of canopy on a 5’ plant. Maybe this is just a misconception from inexperience?

On the idea of a 4x4, can you expound? Like a single 4x4 for everything? Or one for each veg and flower?

I was thinking of a full run in a single 4x4.

Penetration was argued a lot on RIU in recent years. I don't think I ever heard a good explanation of why light from a cob would penetrate farther than light from a board or strip. Most of what I've heard is just really bad analogies.

Food for thought... Why are almost all lights boards or bars now? How does light penetration occur, what is the process? Do the photons pass through the leaves? If so, how can those leaves make use of those photons? Why would photons from the diodes on cobs penetrate farther than photons from diodes on a board or strip?

 

[Boatguy]

I was thinking of a full run in a single 4x4.

Penetration was argued a lot on RIU in recent years. I don't think I ever heard a good explanation of why light from a cob would penetrate farther than light from a board or strip. Most of what I've heard is just really bad analogies.

Food for thought... Why are almost all lights boards or bars now? How does light penetration occur, what is the process? Do the photons pass through the leaves? If so, how can those leaves make use of those photons? Why would photons from the diodes on cobs penetrate farther than photons from diodes on a board or strip?

I truly loved my old cob fixture. If you know anyone with an old 4vs fixture i would love to have it in my 3x3.
Cobs need to be kept farther away than boards, but i saw larger flowers than now with boards. Quantity is about the same

 

[organicnugz]

I was thinking of a full run in a single 4x4.

Penetration was argued a lot on RIU in recent years. I don't think I ever heard a good explanation of why light from a cob would penetrate farther than light from a board or strip. Most of what I've heard is just really bad analogies.

Food for thought... Why are almost all lights boards or bars now? How does light penetration occur, what is the process? Do the photons pass through the leaves? If so, how can those leaves make use of those photons? Why would photons from the diodes on cobs penetrate farther than photons from diodes on a board or strip?

Just wanna start by saying, I’m not attacking you in any fashion when I ask these questions, as I’m a genuinely curious person and want to learn as much as I can, and I have a high standard for accepting arguments.

On the topic of the 4x4:

Why a full run in one tent? I’ve watched a lot of growers and they all seem to end up moving to a separate veg/flower tent setup, so I figured I’d just start there. Not necessarily opposed, but if I'm going to end up in separate tents, I'd rather just buy them on BF sale right meow.

On the topic of the COBs:

Bare with me, this is gonna get long.

I'm going to use full power for calcs to make the math a little cleaner. https://www.waveformlighting.com/horticulture/convert-lumens-to-ppf-online-calculator - found this and using this to convert lumens to PPF. May not be 100% accurate, but using the same calculator for all problems, so error should cancel out and give us a relatively good idea of what we're looking at. One CXB3590 PRO9 @4000k @CRI90 will emit something in the neighborhood of 13,375lm at full power. In my design, I’m looking at 60deg. lenses. I'll reduce the lumen count by 10% to account for refraction and absorption of the lens => 12,037.5lm. Using the calculator, this gives us 214.54 umol/s. At a height of 6.5ft, a 60d. lens gives a total coverage for the COB of 44.16ft^2 =>4.1025982m^2. Therefore, PPFD=(214.54umol/s)/4.1025982m^2=52.29 over that area. This is actually low, since the size of the tent is smaller than the area that the COB would theoretically cover, given no tent to trap the light in. So, to keep things consistent, we have to do the math for the bar light the same way, and not account for the tent trapping light. I'll cover the real equations afterward. A Samsung LM301HEVO diode has a beam angle of 120d. and emits 0.56umol/s. Long story short, the total surface area that the photons from that diode would cover, if uninhibited, would be 398.2ft^2=>36.993991m^2. This gives us a PPFD of (0.56umol/s)/37m^2=0.015umol/m^2/s. Scaling this up to make the power calcs match gives us: CXB3590 72v @1800ma= ~130w dissipation. LM301HEVO dissipates 0.2w per diode at max power, according to its data sheet => 130w/0.2w = 650 Samsung LM301H EVOs to equate the same power dissipation as the COB => I would have to stuff 650 Samsungs into the same area as a COB to dissipate the same wattage (which just isn't physically possible without making an EVO COB with all diodes on the same die). Using PPFD: CXB = 52.29umol/s/m^2, LM301H EVO = 0.015umol/s/m^2 => (52.29/0.015) = 3,486 EVOs required to create the same PPFD in the same area. 1x CXB3590 has dimensions of 34.85mmx34.85mm = 1,214.5mm^2. 1x LM301H EVO has dimensions of 3.0mmx3.3mm = 9.9mm^2 (the diode body is 3.0x3.0, but the anode/cathode bars make it slightly larger) => 1,214.5/9.9 = 122.67 EVOs would have to fit in a 34.85x34.85mm space (not happening) to create the same point source of light as the COB.

The moral of the story?

COBs, while less efficient at creating usable PAR/w than the EVO/SMD chips, creates tremendously more light in a specific area (given lenses to direct the light) => has a higher PPF, and has a smaller total area to cover => higher PPFD over this area than any amount of SMD chips, due to not physically being able to stuff enough EVOs in the same area as a COB. Leaves can only capture a certain amount of photons given a certain surface area => if that threshold is exceeded, the remaining light will be: 1) absorbed by the plant and cause burning 2) attenuated by the plant, then released as another photon once the maximum energy the plant can absorbed from that photon has been absorbed 3) reflected back as the original incident photon (most of the green light that reaches the plants go through this).

Having said all of that, I would likely peg the reason as to why everyone is switching to bar lights as:
- Most people use COBs without lenses => 115d. beam angle => lower PPFD rating than I have stated => Far more even distribution overall => SMD boards outperform because of the next bullet point.
- Far more efficient at creating PAR/w

However, I would be willing to bet that these two systems would work pretty wonderfully in tandem, given the correct distribution of each. As, in my layout (picture) attached to the original post, I would put COBs around the edges of the tent to give directed, high PPFD to trouble areas (areas on the boundaries of the good PPFD given by bar lights) to illuminate them properly, while putting EVO/SMD chips in the center (at approximately the same height, maybe a little lower) to reduce the occurrence of hotspots that are generated by fixtures sitting directly over the center of the tent => ~500PPFD from the center EVO lamp, and ~500 PPFD distributed around the very edges of the canopy to allow light to 1) fill in those shady gaps at the edges of the tent and 2) allow a lot of that light to filter down the sides of the tent, effectively creating side lighting. You will lose some of this to attenuation by the tent, but this is relatively negligible (reflectivity of 95%+ on tents. In my case, gorilla claims something like 98-99%+).

That's my thoughts, at least.

Re-reading your post, I'd like to answer a couple things directly:

How does light penetration occur, what is the process?

Photons DO pass through the leaves. These are quantum interactions, and are simply a matter of probability, though that probability is relatively low that a photon straight passes through the leaf. If, a photon were to hit a leaf, and not be absorbed, it will likely 1) be attenuated and then a lower-energy photon released 2) undergo particle interactions, lowering the energy of the photon => producing a photon with a longer wavelength => leaves underneath that leaf will have longer-wavelength photons available to it (very small fraction). Past that, a higher PPFD = more photons per volume = more chances for a photon to be reflected off another surface onto a lower leaf => "side-lighting effect".

If so, how can those leaves make use of those photons?

They can't, the photon passed through them. The leaf underneath of it could, though.

Why would photons from the diodes on cobs penetrate farther than photons from diodes on a board or strip?

The photons from a COB are not special photons, and have no particular attributes that lend themselves to "penetration" any more so than from any other type of light. The "penetration" comes from the intensity of the PPF in a given volume => leaves can only absorb so many photons at a time => supplying additional photons will result in free photons being available for other leaves. This may, also, cause burning. You will have to watch out for that, and (re)move leaves that are sitting too directly in the intense beam of light.

 

[organicnugz]

I truly loved my old cob fixture. If you know anyone with an old 4vs fixture i would love to have it in my 3x3.
Cobs need to be kept farther away than boards, but i saw larger flowers than now with boards. Quantity is about the same

Any difference in quality, since not a lot of difference in quantity? Seen lots of people grow with COBs and were super happy, but the bar lights allow such nice distribution that it seems everyone just went the way of surface area of the canopy, and not volume. So, you can flower the whole 4x4' space, but only to 1' deep or so in the canopy, minus any outlying, really tall tops that stick out above the rest of the canopy. Whereas, it seems like people before were directing a lot of light in, mostly, the center of the tent (say 3'x3' - 3.5'x3.5'of really good light in a 4'x4' canopy) but were able to flower out maybe 2' of canopy, with likely some lower quality buds in the lower part of that canopy.

I love theory-crafting while I wait for everything to get here haha.

 

[Boatguy]

Any difference in quality, since not a lot of difference in quantity? Seen lots of people grow with COBs and were super happy, but the bar lights allow such nice distribution that it seems everyone just went the way of surface area of the canopy, and not volume. So, you can flower the whole 4x4' space, but only to 1' deep or so in the canopy, minus any outlying, really tall tops that stick out above the rest of the canopy. Whereas, it seems like people before were directing a lot of light in, mostly, the center of the tent (say 3'x3' - 3.5'x3.5'of really good light in a 4'x4' canopy) but were able to flower out maybe 2' of canopy, with likely some lower quality buds in the lower part of that canopy.

I love theory-crafting while I wait for everything to get here haha.

It really depends more on your environment.
In my basement in the winter (the only time i grow indoors) temps can be a problem. The cobs generated more heat but needed to be kept farther away than the boards. So its a pro along with a con.
I dont like doing alot of training and cobs suited that style. I did get longer larger cola's with cobs, and quality wasnt noticeably better or worse. Quantity wise per sq/ft is definitely higher with my boards but that is probably more due to the additional training.

 

[Rocket Soul]

Yeah, they put out an upgraded version of the CXBs recently, giving 15% boost in efficacy at 90+ CRI, so you can get the same or better performance from the high CRI chips as you can with the lower CRI versions. I’ve seen that 4000k at 90+ CRI is very close to true sunlight spectrum, so I was hoping to bring that in. I had contemplated side lighting, but, back in the past everyone seemed to say side lighting wasn’t worth it. Of course, that was before the monster leaps in LEDs.

Do the bars/strips/boards have the penetration to flower anything deeper than 12” of canopy? My main issue is that I don’t see the point in growing a monster plant just to lollipop the bottom 50+% off of it, and spend all that time/energy on it. I do understand why we lollipop, and am definitely intending to, just would like to be able to flower say 2-3’+ of canopy on a 5’ plant. Maybe this is just a misconception from inexperience?

On the idea of a 4x4, can you expound? Like a single 4x4 for everything? Or one for each veg and flower?

90 cri efficacy boost; are you sure this is legit for growing? As in ppf/w boosted rather than just lum/w? This was the case of bridgelux, they had a fancy new 90 cri spectrum boosting lums but not really the ppf.

The P-word: theres not even any consensus what penetration is or how you measure it. What is your definition? Light intensity inside cannopy or how far down you can get buds?
If youre talking about how much light under top cannopy: there is very little in comparison to top. Maybe 10-20%, not enough to drive bud formation on its own. If youve got a grow going already then id suggest you do the measurements to convince your self.
If youre talking about how far down into the cannopy you get buds: thats not really dependant on intracannopy light levels (nor is it completely independent from intracannopy), its about your plant management, pruning sucker growth to prioritize better bud sites and just general plant health and vigor. This is one of the reasons to lolipop; do diminish the amount of budsites in order to concentrate bud growth where you want it. If you flower 3' of cannopy rather than 1-1.5' youll end up with smaller buds all around.


In our grow weve seen nice 5-7g buds deep down into the cannopy where light was like 50ppfd; if this was down to light levels how can you grow a 5g bud in 50ppfd? Its about total light photosynthesis, not just about light levels in the cannopy (which would be too low to drive bud growth in it self even if you use cobs with lenses). If you still feel cobs is the way to go theres a thread about cobs and optics that you may like : https://www.rollitup.org/t/lens-and-reflector-optics-for-cob.893660/page-11

Im not sure but it sounds like youre setting up a first grow going a bit overboard on theory and planning.
My advice for you: start with the one light that you had thought of as the centre light. If you get a light which have an mix of 301b + evo h thats a plus. Try growing with it a bit and get a feel for it. Then start adding things around it. My advice if you want a nice even light spread is to use strips but spec the perimeter so that you can dial in any desired light levels. Using cobs is not really advantageous as it may seem. Just run some strips around the perimeter on a separate driver. If you still want more light into the cannopy try side lighting. Best of luck

Edit: also check out viparspectra bar lights as per advice above; iirc they have bars with asymmetric diode density: more diodes on the end wides of the fixture to promote nore even coverage and extra intensity on the sides. Pretty sure it was vipar

 

[Hollatchaboy]

I truly loved my old cob fixture. If you know anyone with an old 4vs fixture i would love to have it in my 3x3.
Cobs need to be kept farther away than boards, but i saw larger flowers than now with boards. Quantity is about the same

I have a 4vs. It worked great for me!

 

[leatherbackturtle420]

Gavita 1700e
Fluence Spyder.
Synce LED Raging Kush 2.


Ill never buy mars hydro stuff again. Wont even take their stuff for free after what i went through with them.

2 tsl2000s, a tsw2000, and an fce 4800 have all caught fire or wires melted.
The TSW 2000 was only 3 months old and they didnt even honor their warranty.... Trashy company imo.

 

[MissinThe90’sStrains]

Gavita 1700e
Fluence Spyder.
Synce LED Raging Kush 2.


Ill never buy mars hydro stuff again. Wont even take their stuff for free after what i went through with them.

2 tsl2000s, a tsw2000, and an fce 4800 have all caught fire or wires melted.
The TSW 2000 was only 3 months old and they didnt even honor their warranty.... Trashy company imo.

My friend had a similar experience with Spider Farmer. He had a new sf 1000d panel arc and show a burn spot within the first few weeks. He sent them a receipt when they asked for proof of purchase. They kept it and told him to screw off. Another entry-level company to cross off the list.

 

[Jonesfamily7715]

I've seen the pro 9 shit cree has been coming out with, been wondering if it'll be any good for growing, they're actually cheaper than normal cxb 3590 last time I checked. I went with cmu2287 my last cob purchase, right before the pro 9 versions came out. These 95+ cri cobs work great.