(dis)Advantages of LED Lights

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

“What are the advantages and disadvantages of LED lights”


  • Extremely efficient
  • Low electricity usage
  • Low heat produced


  • Technology is advancing monthly
  • Light penetration

LEDs are great for small spaces or for grow tents that have to be worried about heat! I personally have both, LEDs and HIDs. I love them equally lol



Have you noticed a difference in yield or quality between your LED and HID?

Good question. It’s one of those things that I would honestly just be guessing if I said one was better for my own grows. People will say one yields more but I can’t really tell any difference. That could be because of my grows though, where as with others it might be really easy to tell the difference in growth from LED to HID.

This next harvest, Iced Grapefruit, will give me a better idea of whether or not the LEDs are better than, equal to, or less than the HIDs.

I used LEDs for the first time in veg for this plant, and she grew extremely well, so as far as veg growth I think they’re equal. For flower growth I will have to wait to give you a truthful answer!



That’s interesting. I will be growing in a tent inside the house for the winter and most keep telling me LED is the way to go but I’ve been leaning on HID w/ a cool tube just because it’s what I know. I have plenty of time to decide though.
If you do notice any substantial differences w/ your Iced Grapefruit maybe post a log. I’ve done plenty of “Googling” on the matter but we all know (or should know) how reliable that can be. Thanks!


I will definitely let you know @HCHGC! I have a 600w air cooled hood (MH) in my veg tent. For flower it’s 2-300w MarsHydro LEDs. I have to vent the heat out from the air cooled hood, but with the LEDs I don’t have to worry about heat. It’s a huge bonus to me for using LEDs.

If you need heat, then HIDs are the best option hands down. For me, I need less heat most of the time lol!


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I love my LEDs. Light penetration was a concern, so I looked for a light panel with a high PAR wattage. (Photosynthetically Active Radiation). You want to be careful though when comparing PAR wattages between different lights.

The lower the height of the light the higher the PAR wattage will be. In other words, the closer the light is to the plant, the better the light will penetrate. As you raise the light, the ability of the light to penetrate the canopy decreases. This means light A with a PAR wattage of 779 at 18" may not be better than light B with a PAR wattage of 583 at 24". For rough calculation purposes, PAR will decrease by an average of 50% for every 6" increase in the height of the light.

In the above example of light A having a PAR wattage of 779 at 18", if you raise the light to 24" you are looking at an approximate PAR wattage of 390. Therefore, light B with the PAR wattage of 583 at 24" actually has better penetration than light A.

When looking at PAR wattage, these are the numbers I look for based on the LEDs equivalent wattage:

___________ 6" _____ 12" ____ 18" ____ 24"
300w ___ 2288 ___ 1102 ___ 512 ___ 313
600w ___ 3400 ___ 1460 ___ 720 ___ 455


First time growing using Meizhi still seedlings they seem to like it. I think the 900 watt led does put out some heat .

That’s what we needed, someone who knows their stuff!!


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Thanks ktreez! :slight_smile: Most of what I know I learned from this forum.

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Lol ya I couldn’t have asked for a more detailed explanation. Is the “PAR wattage” your referring to the actual wattage of the LED or the equivalent wattage? Or is it a separate measument from the two? I’m a little confused since I’ve never heard the term or used LED period. You kinda just blew my mind :stuck_out_tongue_winking_eye:


PAR is the range within the light spectrum that plants use for photosynthesis. It stands for Photosynthetically Active Radiation and falls between 400nm-700nm (think photons). PAR is technically measured in micromoles, not watts (I used the term PAR wattage generically). A micromole is equal to 602 quadrillion photons (that would be 602,000,000,000,000,000 photons) per square meter, per second. In other words, PAR is the photosynthetic photon flux density of light, per square meter, per second. This differs from Lumens, which are used to measure bulb brightness and watts, which correspond to the power in an electric circuit. Since plants require different wavelengths, when deciding on LED grow lights, it’s the PAR (not Lumens) you should concern yourself with. This is because PAR is a more accurate measurement of what your plants are actually absorbing. I mention this because most LED manufacturers tout the Lumen output of their LEDs.

Keep in mind though that In addition to PAR, you also want to match the wattage to your space. You want a minimum of 32 watts (about 18 true watts) per square foot during flowering. You can get away with half this during veg. This is why you want a light with veg and bloom modes.

I use veg only mode during veg, full spectrum during flower, and bloom only during flush.

:stuck_out_tongue_winking_eye: :upside_down: :stuck_out_tongue_winking_eye: :upside_down:


So in basic terms lumens is the measurement of light output, Kelvin is a measurement of light temperature (spectrum) and PAR is a range of what the plants can absorb within that particular spectrum?

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just expect less with less expenses - yield will drop to .75 per watt with Led
But so does the electric and heat bill - Grow more

Without getting involved in flux capacitors and giga quadrillion par lumenachingythingy’s (great stuff @GrowManFitz )

I am using 2 meizhi 1200w. And 1 marshydro 144 reflector series… and 2 4ft 8bulb CFLs. I think I would rather have 4 600W meizhi’s than just the 2 1200, just for more flexibility. Don’t get me wrong… I love the lights just wish I had a little bit more flexibility as I’m growing in 2 different tents and learning as I go.

Best of luck to ya… it’s fun, it’s addictive, it’s frustrating and relaxing all at the same time… some days you gotta get high to calm down when you snap off one of your mains… sometimes you shouldn’t have been high when you were trying to tie down one of your mains.


Snap off a main, yell a few choice words then run as fast as you can and grab the honey and the duct tape! LOL!!!


Lol @GrowManFitz (and by the way, I agree for the most part of your claim, good job :+1::ok_hand:) :sweat_smile: :joy: I will post further on a topic that, I hope, is gone a put some enlightement on this subject…:wink::grinning:

~Al :innocent: :v:

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Inexperienced grower here and need some advice. Ive got a plant about 2 months old growing outdoor and I want to move it in to a cuboard under a light. Is this possible or will the change kill it??? Im in love with her and dont want her to die.


No it shouldn’t kill it as long as you give it everything it needs. Don’t skimp on the light is all I can say. And try to keep the same hours of light going so it don’t flower on you !