HPS/MH, LED wattage

Recently switched from MH/HPS to LED, verdict still out as I'm still in veg. but it does look promising. So the debate on wattage between HPS and LED is puzzling. Is not brightness what we should be measuring? Who gives a flying F. about stated wattage. I purchased a LUX meter for my LED's and it made me wonder why all the debate on wattage when brightness is what we should be measuring. Am I wrong?

So seedlings do well under 8000 to a 10000 lumens any more seems to stress the tiny guys. Veg. right now they are eating up 18,000 and I feel can handle more. Trial and error on first go around. Not sure on bloom as it is a couple weeks before we need to fire up Bloom-oplis.

What say you?

What you are questioning is the central problem when comparing different light sources. Trying to find a metric that allows you to have a direct comparison is confusing. Watts are what we end up paying for when generating light from electricity but the rub is finding how much light we get from each watt paid. Your lux meter is useful but because of the 'bias' it measures to simulate human vision it may not be linear in reading some of the wavelengths that 'blurple' led panels produce. Best metric I've found is PAR, This allows you to compare total light output and calculate efficacy if you know how much wattage the light uses.

So I need a par meter? Will research. Thanks

A decent par meter is over $300. Just buy an extra light

hotrodharley said:

A decent par meter is over $300. Just buy an extra light

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You get the right LEDs you won't have to measure them. They will do there job so well, cheaply, and efficiently... you'll know you made the right call to switch ha.

So my issue is just switched some girls to bloom. New room 1st use. In my veg. room I get a lux reading under my 4500k led's of 22,000 lumens and it starts to stress the plants. 20,000 seems to be the sweet spot. In bloom I have 3000k and 3500k led's and the lumuen reading is 12,000. Understand light is not as bright due to "k" ratings. Maybe normal?? What are you getting for lumens on 3000 and 3500k led's? At 12,000 lumens I am about 8" from plants... nervous seems too close will advise how the girls like it!

Which led light did you go with and why?

Gilligans Island said:

So my issue is just switched some girls to bloom. New room 1st use. In my veg. room I get a lux reading under my 4500k led's of 22,000 lumens and it starts to stress the plants. 20,000 seems to be the sweet spot. In bloom I have 3000k and 3500k led's and the lumuen reading is 12,000. Understand light is not as bright due to "k" ratings. Maybe normal?? What are you getting for lumens on 3000 and 3500k led's? At 12,000 lumens I am about 8" from plants... nervous seems too close will advise how the girls like it!

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I think what you're seeing is why using a lux meter is challenging with leds. Because of the 'weighting' of particular wavelengths of visible light, you see a much higher reading under the bluer 4.5k and less under the 3k. Only way I can suggest using your meter would be to use it to replicate known intensities that your plant can tolerate-which is what we do anyway. It just makes it so that you can duplicate conditions consistently.

Fatleg77 said:

Which led light did you go with and why?

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Bridgelux EB series. DIY'd the frames. I only have 69" of ceiling height. Had to go led, looked at Samsung's strips but did not like the double row as I feel better distribution with led's spread out more. Could not go with pre made units as hot spots with such low ceiling would be an issue.

GBAUTO said:

I think what you're seeing is why using a lux meter is challenging with leds. Because of the 'weighting' of particular wavelengths of visible light, you see a much higher reading under the bluer 4.5k and less under the 3k. Only way I can suggest using your meter would be to use it to replicate known intensities that your plant can tolerate-which is what we do anyway. It just makes it so that you can duplicate conditions consistently.

Click to expand...

Agree and this is what I figured was going on as I was only getting half the reading under my 3000, 3500k lights as compared to my 4500k. I will just use it as the gauge to figure out my distances from led's to plant without burn and continue to look for a reasonably priced par meter. Could get by without I supposed once I figure out my distances. Already trashed one round of seedlings under my florescent. ANC had indicated keep seedlings 2" under 23 watt florescent which is probably perfect. But that distance is no good for 40 watt 4500k. Opps. Had to toss them, fried by the lights at 2 weeks. Now 4" on 40 watt is perfect. Next two cycles have been thumbs up so far.