Can any led compet with a double ended bulb ?

prune said:

I don't see it that way. Most of a DE's output is actually reflected and by that effect diffused.
LED light is mostly unidirectional with no diffusion other than atmospheric refraction. Any leaf not under the sweet spot, or any leaf shaded - gets bubkus.

and let's not even get into penetration... (lol)

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You sure about that? This is the light spread of a typical white LED (cree 5630) with no diffusor, just the LED itself. So at a 45 degree angle to the light you get 70% of the lumens you have directly underneath it.

This talk sums it up quite nicely. As of 2018, HID is dead unless it comes up with some new and unexplored avenue.

https://youtu.be/H92g1SFFDKo

Douglas.Curtis said:

This talk sums it up quite nicely. As of 2018, HID is dead unless it comes up with some new and unexplored avenue.

https://youtu.be/H92g1SFFDKo

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So someone trying to sell LEDs says HPS is dead, yeah ok

Remember when we were screwed by the American Government once again and told that the incandescent bulbs were being phased out and replaced by energy efficient technologies. Same thing is coming for the Halide, Sodium as well as the fluorescent lights. Its going to get interesting in time when bulbs are limited and hard to find like 13" auto tires ..

Yea, I see a lot of claims on what led's can do, but I haven't seen any solid proof that they can out perform a HID. I've done a lot of research, but can't really find anything convincing. I wish I could change all of my 1000 hps lights for led's, that would be nice. Guess I'll have to buy a tent and test out an hlg 550 v2. If it doesn't meet my expectations, I'll use it for personal. Hope it does though

OP

I only see trouble with people not understanding numbers/specs and making absurd quick conclusions about light vs light.
Things are not straightforward and even if there was a led to replace a de hps, if used the same way as hps won't perform at its best.
Different lights need different setups, nutes, canopy management and so on.
So don't expect to just switch lights, you'll need to update the growing routine to get the max out of a led light.
Hps 1000/600 still work great if one can use them properly.
And from what i believe, a 1000w hps can only be matched with at least 600-700w of top performing leds, less than that will likely produce less than a 1000hps.

Cheers

If the PPFD is the same, why would the yield differ?

Mainly because of different light spread, canopy management is very important to get the most out of it. Also hids bring an extra IR spike, so temperature management should be different, the fuller spectrum means a bit different nute uptake and so on.
Everyone switching to leds should get a couple of cycles just to dial in the parameters and of course to understand better the plants reaction to a different spectrum.


Cheers

Oliver Pantsoff said:

Yea, I see a lot of claims on what led's can do, but I haven't seen any solid proof that they can out perform a HID.

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There are several growers on icmag alone, who have been testing LEDS for the last few years. Some have even been doing side by side testing of all new lights, including HID lamps. Go find them and their posts like

WTF? Why do I care what people think about LEDS. LOL Whatever you wanna believe, go buy those lights. lol What a waste of typing here.

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0099010

I think the best way to answer that question is read that article. I don't see any LEDs that beat the photon efficiency of the DE HPS in the charts. Have any new LEDs since 2014 exceeded 1.7 umol/J?

Douglas.Curtis said:

There are several growers on icmag alone, who have been testing LEDS for the last few years. Some have even been doing side by side testing of all new lights, including HID lamps. Go find them and their posts like

WTF? Why do I care what people think about LEDS. LOL Whatever you wanna believe, go buy those lights. lol What a waste of typing here.

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Yeah, thanks for the 1st half of the reply. I don't know what the hell was going on with last part of the reply. Dude, chill, and go smoke a jernt..Its not that serious. We're all here just choppin game about lights..

OP

Biologist said:

I think the best way to answer that question is read that article. I don't see any LEDs that beat the photon efficiency of the DE HPS in the charts. Have any new LEDs since 2014 exceeded 1.7 umol/J?

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2013/2014 came out the Cree CXA, a game changer. The newer CXB is usually over 2.6 umol/J.

Cheers

Correct me if I'm wrong but the photons in PPFD measurements are not weighted.

So, it's possible to have a higher PPFD but a lower YPF (yield photon flux). I.e.: 2 lights can the same PPFD but plants photosynthesize less due to a difference in spectrum. Lower wavelength light is about half as efficient as red light when it comes to photosynthesis per photon... we all know where the sodium light spectrum is, especially at high power.

Do you remember the purple 185w leds touted as 600w HPS equivalents? Now, we are getting PPFD advertised. But maybe it's still not the full story, and LED manufacturers are profiting from this? Surely they know about photon weighting. All the leds have significantly more energy in the low nm light spectrum.

The only 2200k, 2700k leds I've seen are very inefficient compared to 3000k and 3500k. Yes, the 5000k led can do 3.1 umol per joule. Bless the lettuce growers but I'll pass.

I'd like to see LED with the same spectrum and IR etc of HPS. I don't believe that a single light source can "penetrate" better than many light sources providing exactly the same intensity. The only place where it would penetrate better is the hotspot under the bulb getting maximum intensity light. The HID sources penetrate in a V shape , superior in the middle and inferior at the edges. While the led intensity/penetration is more flat and even for obvious reasons.
The only other thing that matters for penetration is spectrum because different wavelengths are absorbed or reflected differently by the plant... Or they can pass through with more or less ease.

Then there is the radiant heat which is actually sometimes a better thing than people seem to realize? Outside of hot summers. Just look at data on the correlation between transpiration and Yield. When do the plants transpire optimally? Of course, when it's like 85F. With HID it's easy to raise the leaf temperatures if that's whatyou wanna do.

Anyway we all know LED is getting better rapidly, HPS is still on DE, and weed is practically legal in the place that made everyone ban it in the first place. If you're still wondering in 2019 just wait 2 years and there won't be any more comparing I think

edit: The best source of information on lighting in horticulture currently may be Bruce Bugbee and his associates. I challenge anyone to find someone better because I would love to read that person's work. In this thread I have linked a recent presentation by his; on youtube there is more information from him. He does not sell lights but works for university and also for Apogee, who, as far as I know have no interest in selling light, but rather in measuring it.

Thanks for sharing the link to Dr. Bugbee's presentation.

Jumpin' Jesus! I have installed 3 LED bright white light 2' panels. I purchased these at Home Depot in the States. I can not tell the difference in LED's but I figured I would give these a try because they are High Bay LED's. I run them about 3-4' above the plants as they stretch. The lights are spectacular and the results on the plants are immediate. Very nice indeed.

Maina said:

Some one is trying to tell me a led out there that can compete with a gavita 1100 I say no way ! What do the pros say ?

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Independent side-by-side grow tests show that our lights consistently produce at least double the grams per watt of HID, and those results date all the way back to 2010 (in fact many of the grows were done here on ICMag which you can see in my signature). So for nearly a decade now we've been beating HID rather than competing with HID.

The reason for this is that "white light" was never designed to grow plants. Sure it can grow them and yes, you can get decent results with them, but that's only if you consider half the yield per watt decent (and for some people, they're ok with that which is cool).

We are one of (if not) the only LED company that since day one has challenged members to put our lights next to whatever you grow with and run a side-by-side. We didn't release our first product until it was besting HID in our own grow ops. We actually want you to see who's light works better for you, whereas our competitors just want to show you "hey our lights work". And well yeah, pretty much every light these days will work lol. It's like saying "cars work", but a Ferrari is going to get you there a lot faster than a Hyundai.

gladysvjubb said:

Jumpin' Jesus! I have installed 3 LED bright white light 2' panels. I purchased these at Home Depot in the States. I can not tell the difference in LED's but I figured I would give these a try because they are High Bay LED's. I run them about 3-4' above the plants as they stretch. The lights are spectacular and the results on the plants are immediate. Very nice indeed.

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Please stop pimping these lights. They've been real world tested and are garbage for cannabis. Yes, they're better than some, no they're not cost effective.

ty

^^ what Dougie said ^^

gladysvjubb said:

I do not know. I have 56-60 plants all in individual pots Each is an individual with it's own traits. I just water them when they wilt a little. But I have very nice growth. Strong plants. Nice smoke. I just filled a jar with Acapulco gold. Eyeballing it I would say that my 5 plants produced about 1 oz of dried. But it is for me. I smoke all day every day. I have 10 Bruce Banger germing right now and 5 Zamaldelica. They will stay in the veg cabinet for 3-5 weeks. The factory is humming along nicely.

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You should be pulling a minimum of an oz per plant. Still believe your light is super duper?


start of week 4 in flower. Canopy height 36" Light 48" from canopy PPFD 800 umol

HydroGrowLeds said:

Oops

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It is all well. But, I saw you. Folks need to read, 1st. He quoted a post from @ gladyvjubb That has been spamming his home depot light since Christ was a cowboy.