Is my led too close?

NanoGadget said:

All I'm going to say here is that I've bleach the shit out if the tops of my colas at 14 inches

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I have to assume you had very poor uniformity, and you did not measure the PPFD.
How many got bleached? Not all of them.

I also forget many of these units do not have dimming circuitry. Where you put the fixture as close as you want then adjust the PPFD to what you want. I have never had a fixture without a dimmer. And I use wide angle OSRAM SSL150 LEDs without optics to get good uniformity at minimal distance between the fixture and canopy. And I have the app that simulates the spacing and height to find the optimum height and spacing.

I do everything possible to minimize the height. The Inverse Square Law is important. The power can be reduced to 10% (one tenth) when the height is lowered from 19" to 6". Cutting the electric cost 90%.

A lot of the box type fixtures narrow angle optics that concentrate the slight into a smaller footprint and designed for a higher height. That does not make sense to me. The only reason to do that is to be able to publish a spec with a high PPFD. I did look for optics on the box before. At 400 Wall Watts that unit is not very powerful with epistar LEDs. The uniformity is important as I mention. 6" IF the light spreads across the canopy. If the uniformity sucks and the light is concentrated in one spot, then no it cannot be done.

I assume you read my diatribe on Watts. Watts doesn't mean Jack Shit! What matters is the intensity of the photons hitting the canopy. When people buy a fixture based on Wall Watts you are only encouraging the vendors to use shitty inefficient power supplies. Buyers need to smarten up. And yes, I know that is not easy. It's a nightmare out there. The is a shit load of things between the wall and the photons exiting the LEDs that can degrade efficiency. Heatsinks and thermal management are expensive. Temperature degrades efficiency enormously. But if you buy on wall watts the vendor can fuck everybody. And that is what they are doing. The use inefficient epistar LEDs, shitty power supplies, and only enough thermal management so the LEDs do not die during the warranty period. And they get to charge more for doing a shitty job because the buyers are uneducated in how to choose a fixture. The most important thing is the amount of radiant flux, the PPFD. Then uniformity. Then the amount of electricity. Then the cost. A dimmer is a very good feature.

You must also understand the "Reviews" are paid advertisements. Likely everyone of them.

18" .... Both switches on ..... Plants happy

HydoDan said:

Real world experience not growing on paper.

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If that was aimed at me, fuck off, that would make you clueless. It's my fuckin' job.

HydoDan said:

The only light you can run that close is a cfl..

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That is not true. You just need to buy better fixtures. And do better at buying fixtures.

Actually my uniformity was decent. The problem was the system I had cobbled together to hang/adjust the height of the light malfunctioned and I didn't catch it right away. Obviously the bleaching was most intense in the center where the PAR is highest, but it affected damn near the whole canopy. Also, even though it's an older light (in terms of LED systems) it does use OSRAM SSL emitters.

NanoGadget said:

it does use OSRAM SSL emitters.

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Probably the SSL80s. When the height is getting close to the canopy inches in height increases power logarithmicly. 50% reduction in height is a 4x (400%) reduction in required power.

If you have a PAR meter, uniformity, and dimming, you can significantly reduce the electric.
The box fixtures have to cram in the LEDs. Ideally LEDs would be spread out for uniformity and allowing the fixture to be close to the canopy but those metal core PCBs are expensive. Everybody accepts that obstacle and deals with it. I don't accept it. I found a solution. Look for the problems and solve them. Nothing is impossible until someone does it.

NoFucks2Give said:

If that was aimed at me, fuck off, that would make you clueless. It's my fuckin' job.

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No you FUCK YOURSELF!!! Just added to my ignore list.. Nothing to learn from you ass wipe!! You have posted no pics and have no real growing experience .. just a bunch of googled info.. what a dumb fuck!!!

NoFucks2Give said:

That is not true. You just need to buy better fixtures. And do better at buying fixtures.

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Fuck you.. been growing for close to 50 years.. You know nothing dumb fuck!!

NanoGadget said:

All I'm going to say here is that I've bleach the shit out if the tops of my colas at 14 inches with my CLW Solar Storm 440 which draws 350 watts at the wall. If I'm not mistaken 5he OP said he runs a Vipar 900 which pull about 400 at the wall. If we assume that it runs at approximately the same efficiency as mine and puts out similar PAR levels then 6 inches is way too close.

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I second that ... indeed the cat looking for advice was going to fry his plants .. I use the Spectra 450 and with both Veg and Flower turned on, I keep it at about 24" .. and to me that seems to be plenty close enough .. I"ve seen enough around here to believe light burn is real, and does happen with LED's .. the buds I am about to harvest in a week are "textbook" beauties .. only in my wildest streatch of the imagination, would I have dreamed buds the size of my fist are grwoing under my 450 LED in a 3' x 3' x 5' tent.

Instead of seeing how close you can get them, what I have just found to be successful, is getting a light meter and see where the optimal coverage hits the canopy. My plant doesn't want any more than what I"m giving her.

My end product, is exactly what the expert who sells me my supplies, advised. I do as he says, and everything turns up golden.

On my next grow I will try to master preventing the streatch in early to mid veg - Something I haven't done yet with the Viparspectra 450 - i used a spiral cfl that seemed to work well, but I'll check on using the LED this time around.

Problem with LED burn is that you don't see it till after it's too late ... when I see the gorgeous buds under my light, I would'd even dream of lowering my lights in fear of burning off resins, turpines etc ets .. once it's burnt .. you cannot unburn it.

Your veg looks amazing btw .. google what light burn and wind burn looks like .. then google a chart for plaint ailments according to leaf symptoms. The charts are all over the web.

NoFucks2Give, all what you wrote has 100% sense I'd say. I do not see a point to argue with people who believe that only growing is the way to gather knowledge and "paper" growing is less important. HydoDan, I respect all the members here but I disagree that cfl is the only light you can run too close. If you run LED with low power you can make it even better than cfl. There is other advantage using under powered LED and it is their efficiency per watt. Only drawback is upfront investment for LED but anyway if you populate space with very efficient under powered LED strips attached to aluminum profile, you will get very strong light output (almost to the point of photosynthetic saturation, e.g. around 1000-1500 PPFD), low temperature on strips (around 40 degrees if you stick them to aluminum profile) and low electricity cost (2.5-3 micromoles/joule or about 200lm/w). I am biologist and have some experience in growing btw...

NoFucks2Give, you mentioned you have an app that simulates the spacing and height of the light fixture from the canopy. Is that app freely available maybe?

I am constructing LED fixture for 60*60 cm space. Also, regarding efficiency Samsung chips seem promising but Samsung engine calculator provides lumens as the measure of flux. What I did, I converted DLI to PPFD, PPFD to lumens and found that 8 x Samsung LT-F562B strips @3000K run on HLG-120H-C700B would be ooptimal for my area. I will run each strip max @0.7A. Actually, for my grow area 5 strips @ 1.2A would be sufficient, but light distribution is not so good and I decided to go with 8 strips @ max. 0.7A. As the light tend to accumulate in the mid of the fixture, I was thinking to distribute 8 strips more towards edges. It would be great if I can get some app or suggestion that can help me how to distribute strips on a fixture...
Do you have some recommendation on this?

Kcbscrogger said:

They look fine to me it's just new growth is a little lighter, my 600w viparspectra is at 18 inches during veg. Good luck

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I'm doing my first ever grow, I'm using a viparspectra 600w, do you like it, one guy messaged me saying it's not very good?

I'd squeeze those two bitches as close as they can get in the centre. Those lights have a very small usable field.