If I buy an led light for growing I have read 50 Watts is optimal. However this is what confuses me


A customer has a question and I hope we can get some opinions on it, thanks

If I buy an led light for growing I have read 50 Watts is optimal. However this is what confuses me. A light might say 150 Watts but also only uses 15 Watts. So, do I say I have 15 or 150 Watts to use for growing even though I know only 15 is being consumed PR another example is for a 4x4 or 16 square foot tent to grow optimal would be around 400 Watts so do I need 400 Watts being used or say 3000 Watts light but only consumes 450 ?


Always go by ‘at the wall’ wattage


You are looking for a minimum of 50 watts per square foot. 2 600w hps in a 4x4 tent equals 75 watts per square foot you need a minimum of 800 watts for a 4x4. 16 x50 watts equals 800 watt of light to shoot for


IMHO if you want lights for flower 35w/sq ft of the highly efficent LEDs is appropriate… I grow in a 4x4 with 600w (real consumed electricity) of LEDs in a full spectrum (3000K)… I got .89g/W from the last two plants I flowered in there.

For less efficient LEDs like the blurple panels, I think getting closer to 50w per square foot is more ideal.

Now, if I were to use the blurple LED panel nomenclature for my DIY lights, I have three rails with 5 COBs each on them and each of those COBs is rated for a max of 100w. So each rail is a “500w rail” in Marketing Speak. But in reality each rail is consuming 200 watts (40w per COB).

If I were selling a light fixture like it on Amazon perhaps I could name it the BogBright 1500w Grow Light or something… and then in the details tell potential buyers it really consumes 600w…

I think with the lights I have right now if I dimmed them and ran them at 500w they would probably work just fine and produce good results too.


You could always go with a light that advertises what it actually uses. Examples would be anything from timber grow lights or horticulture lighting group. As an added bonus, both companies give you a realistic expected light footprint as well. There are other companies that are good as well, but if price seems too good to be true, it probably is.


Yes 800 Watts is what I meant but do I get enough light or big enough light rated at 800 Watts or a light that consumes 800 Watts hence this for example, say it consumes 800 Watts but is rated at 3000.or say this "I want 800 Watts to grow with from led. So,do I get an 800 watt light that only uses say 80 Watts? Or a light that uses 800 Watts? I hope this makes sense. I don’t know anything about indoor or I am new anyway only know what I study but am still confused by led true wattage. As a matter of fact, there it is,do I go by true wattage? Or what its rated for? Thanks in advance


If we’re using the “watts per square foot” number to determine how much light we need, then the consumed watts is the real number. The “rated” watts is a marketing scheme.

So you would want “a light that consumes 800 Watts hence this for example, say it consumes 800 Watts but is rated at 3000” based on your above options.


Thank you very much because all this time I have been thinking I am really doing good if I buy an 800 watt light that only consumes 80 for saving and all the while my yield would have really suffered. Have a great day!


Thanks as a matter of fact to everyone. A lot of very useful help


I messed up with cheap leds about a year ago and went back to mh and hps i run 2 600w mh and hps lights in a 4x4x6 grow tent. Last harvest off of 6 plants was 1lb 5oz dry. I’m Trying to to figure out what to build by reading the diy lights section to achieve the same thing with my hps lights here is a picture of my grow starting 3rd week of flower right now


I’m willing to bet @Bogleg can hit 21 zips in 4x4. Not in anyway shape or form a guarantee that you would by copying his lighting. But the potential to hit those numbers is there.


We will find out in 5 weeks or so. :wink:


I’m thinking you’ll be there. Personally I think you’d be able to pull bigger numbers with the 2 plant dual screen than the single plant. Just because you’ll have 2 plants doing their thing to cover same area. And I’m also not sold that particular plant is highest yielding in your collection. But I still think it’s realistic number.


I agree on the latter point - but it has the potential to get there and it looks like I set myself up to come close.

But thanks for saying that, now I want to run side by side Cindy screens… maybe in 2019.


I’ll hit you up on the other side I have some questions/thoughts I want to run by you re: SOG.


Yessir, certainly on your way!


That is what I’m trying to understand so when i try led or cob or a combination of the 2 is to get it right. I messed up 400 on leds before and go taken in by all the marketing and hype but getting 21 zips of dry weight of my setup didn’t seem to bad for me @Bogleg is it ok to look at what you posted and ask you about your setup


Absolutely. I have a couple of grow journals if you have a lot of time to kill where I went through the whole process with @dbrn32 of evolving from a guy who yielded 4.76oz on his first grow to a guy who got almost 15oz on his second, and 20oz on his third. If I can help someone else avoid the cost and time associated with my first grow, I will make the effort for sure.

Sometimes there are too many acronyms and names for things going around. A COB (chip-on-board) is a kind of LED:

It’s a whole bunch of diodes packed onto a chip to act as one light… I’m not a light guru, so someone with more technical knowledge can break that down further.

Timber Grow Lights or the Rapid LED lights are good examples of COB-based LED grow lights. Pacific Lighting Concepts is another one I believe.


You are such a tease lol.


Probably wouldn’t have said it any differently.