LED Grow Light Forum

Hello Everyone,
I am new to this forum and came across it by chance but I have a feeling that I may be able to find the answer to the questions I have here. I am growing in a cylindrical VSOG configuration. I have had great success with this using HID lighting, however I would like to move towards LEDs. I am building an octagonal frame for my led array that measures 40" in diameter by 48" tall. Each of the eight panels that attach to the octagonal frame measures 16"wide by 48" tall. This construction portion I have the ability to do, but I am having a bit of trouble finding out if the amount and type of LEDs will work for my application. I am hoping that you all may be able to provide me with some good direction on how to proceed. Here is what I am thinking based on several months of online research. Please let me know if I am way off base with this:

Each panel would consist of 152 3w LED (Bridgelux is what I have) with 60 degree dispersion. The ratio that I have (somewhat) arbitrarily chosen is 660nm @ 84, 640nm @ 22, 470nm @ 24, 445nm @ 6 and 730nm (1w) @ 6. These will be arranged in rows of 8 LED across (spaced at 2"OC (on center) and there will be 19 rows with 2 9/16"OC between rows. I would like to drive these at 24v (I already know the schematic) and the blues and red will be dimmable via PWM to manipulate stretch during flower, as well as help with energy consumption. This array will consist of a total of 1216 total 3w LEDs. Each 152 3w LED panel will be 16" away from the plant site and will illuminate an area of 32" by 54". The questions that I have for those with more knowledge than I (and I am sure there are MANY here) are as follows:

* Is 152 3s LEDs enough to illuminate an area of 32"x 54" effectively? Could this provide adaquate PPFD mol m2/s for this coverage?

*Is 60 degree the proper light spread for this application?

*Do the ratios seem to be on par with veg and flower requirements?

*Would you recommend a single driver, dual drivers (red and blue) or multiple drivers (one for each panel) for this application?

*Is the spacing (approx. 2sq in.) too far apart for 3w led's to be effective?

*Will 3w LEDs penetrate 16" effectively for a SOG style grow?

*Are there any other factors that I should take into consideration regarding lighting? I was thinking of supplimenting during flower with a 600w hps.

I would greatly appreciate any advice on this subject. I know there is a lot of information out there and I have spent a great deal of time reading it, but some feedback on this specific project would really help me put it all in perspective. I already have the LEDs and driver; I'm just not sure if I am applying it all correctly. I suppose I can post a schematic of the LED placement for each spectrum on the panels if that will give someone a clearer picture of what I am trying to do. Thank you all in advance for any advice and considerations.

Welcome to the forums...

This really isn't the kind of forum where people build their own LED lights and much of what you're asking is subjective. That said, I'll give my opinion on one of those questions.

I'd say that 450w is not enough to cover an area of 32"x54", I'd be aiming for 600w for that space.

My advice on lighting is: do not skimp on lighting. That's not to say you need the top of the line, most expensive, light on the market, I mean that growers should aim for the 45-50+w/sqf as a minimum. With LED that gets expensive quick but if you want to grow high end plants, you have to give them plenty of food and light while maintaining other environmental factors. More watts is even better (up to a point) as long as the other environmental settings are dialed in...but too little light is one of the biggest issues with LED grows.


Hope that helps,

SME

Thank you very much for the quick reply. I was unsure about the nature of this forum but I appreciate your reply. Since I have not used LEDs as of yet, I was not sure what a "real" comparison would be to a 1k hid (which is what I currently run). My thought process was that I use a single HID that casts light in a 360 degree spread whereas the LED would carry a much narrower spread per panel. This being said, the overall power consumption would run about 2kw with LEDs to get the same 360 degree coverage. I figured that if I compared PAR for PAR (HID and LED) then I would be casting out significantly higher PAR values with 2kw worth of LED over the same 64sf of growing area. Can you tell me if that would be an inaccurate assumption? Thanks for your time.

Despite most LED marketing claims I think you'd need near 1000w LED to equal 1000w HPS. I've yet to see a LED grow break 1g/w, hid can. I'm hoping that somebody will go over that mark but not so far. Additionally, 64sqf of grow area should have closer to 3-4kw than 2kw. Again, not enough light will impact results.

YMMV... ;