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LED Grow Lights – 3 Watt Vs. 5 Watt Vs. 10 Watt


dorm grow led light marijuanaLED grow lights have come a long way in a very short amount of time. Manufacturers first started using 1/16th Watt diodes and then used larger and larger diodes as the technology advanced. Now you can find diodes even up to 50 Watts and larger, but is bigger always better when it comes to LED growlights? The answer is No. The ideal diode size for LED growlights is the 3 Watt diode.

Although 1/16th Watt diodes are too weak to grow much of anything and 1 Watt diodes by themselves do not penetrate enough, diodes that are too large are also counterproductive for indoor growing. Save the 10 Watt diodes for street lamps. They have no business going into grow lights as they are much more expensive on a $/Watt basis, give off more heat and completely defeat the whole purpose of growing efficiently with LEDs.

The ideal size for LED grow lights are the 3 Watt diodes. The 3 watt diode provides the ideal balance of canopy penetration without having excess heat problems that come with larger diodes. With 3 watt diodes, a grow light is able to penetrate up to 5 feet past the plant’s canopy which is what is needed for commercial indoor growers.

What are the drawbacks of using 5Watt, 10Watt or lareger diodes in a grow light? The first issue is heat dissipation. As the diode size increases, so does the amount of heat that needs to be dissipated by the diode chip. Larger wattage diodes need larger heat sinks to dissipate the heat that they give off. This results in heavier and bulkier lights. The second issue is of chip density. Since the 5Watt and 10Watt diodes give off more heat, they must be spaced further apart to avoid thermal failure. They cannot be packed as densely as the 3 watt chips. The result is a less densely packed grow light that is heavier and bulkier.

The third major drawback of the 5Watt and 10Watt diodes is that they are too expensive. They cost more and are also more expensive on a $/watt and $/ square foot basis. A quick analysis shows that it is not worth paying a premium to have larger diodes in LED grow lights. They are unnecessary for indoor growers and come at a burdensome cost of increased prices, less densely packed network of diodes, and bulkier grow lights.

Bigger is not always better. When it comes to the question of the ideal diode size for indoor LED grow lights, the 3 watt diode is the smartest choice for any indoor growing project.

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Johnny Green


  1. check out sublime 16 module 336 x 3 watt chip hybrids that run induction bulbs… on facebook (sublime illuminations leds) or google it

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  3. indoor grow og kuhs , ak47 , white widow , purple haze and many others for sale . text 970 788 6066

  4. go to mvphydroponics.com You can get about 60 square feet of coverage for that price instead of 30 sq feet. There a lot longer and brighter with 120 degree angle.
    If you go with the 900 watt which actually gives coverage for about 30 sq feet. These LEDs are rated #1 by Master Gardeners Inc.

  5. Irvin Rosenfeld is who you are thinking of, we are talking about the master grower, Ed Rosenthal

  6. Back in the 90’s I exchanged several letters with Ed Rosenthal about using hormones on plants so I have no problem believing he would discuss new lighting technology with someone. If you had good well thought out questions or info to share Ed Rosenthal was pretty accessible via snail mail and later e-mail,

  7. IMO, LEDs are still a few years away from being equal or better than MH/HPS lights based on what I’ve read and seen on various grow forums by actual growers. I’d have no problem mixing them with MH/HPS lights to up the light intensity and spectrum.

  8. you spoke with one of 4 people who can legally smoke marijuana anywhere in the United States? I doubt it.

  9. Vincent Nibblin on

    1800 bucks to cover only a 4 by 4 area! You are fucking nuts!!!!! And only a 3 year warranty!!!!!
    For that kind of bread they should carry a lifetime warranty. You must be rich, or either a moron to buy this product

  10. I recently spoke with Ed Rosenthal regarding the current state of LED lights, I am standing by his findings which show just what I stated. I have also done my own test using the same clones, using exact feeding for each group. On average traditional lights produced 30 to 35% more per plant. I understand you must either work for the LED industry or be sitting on a bunch of product you need to move. LED is good for veg and for filling in gaps in the spectrum. I would like to see if your resume rivals Ed Rosenthal’s. I would think not.

  11. sorry to say but you are incorrect. Like this thread sais: LED has rapidly improved and they are correct with penetration. I have proof. you will be best served in the long run to investigate the independent studies here :

  12. Sure Ive been using recommended LED from progrowlighting.com check it out and get independent studies show the results.

  13. i swapped out my 1000w hps with a G8LED 600W and have never looked back. they are 3watt diodes in there

  14. New to LED, any suggestions for a six plant 2 1000w hps setup as far as 3 watt? Spectrum? Quality brands? Any info would be great!

  15. I bought 10,30, and 50 watt LED floodlights to experiment with… have had them a couple months now… the veg plants love them and… I love the power savings. :O)

  16. LED are great for filling in gaps in the spectrum, but they like the foot candles to compete with halide and sodium lamps!

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