Do you just do a sheet of paper over your lense or build a little cover like in this video?
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I just tape a strip of paper across the top of the face. It works.
I then hold it at the top of the plant then at different colas and make a decision.
I use a rough guide that I found here somewhere.
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Thanks for this info. I’ve tried using the Lux meter app, but didn’t find it particularly accurate as it never gave consistent results for the same locations. I didn’t, however, use the paper trick and I’ll try again tonight after covering the camera and see if there’s improvement.
@Jango I found that the manufacturer’s height and dim recommendations were ideal until I started flowering and I’ve had to adjust a bit there. Going to get this perfect sooner or later haha
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This info came straight from Steven at HLG and worked for me with a 600 Rspec.
50% at. 30" for veg and. 24" full power for flower. Adjust the light up slowly the 2nd week of 1212 until you reach full power over 5 days or so.
This is info Mars Hydro sent me for the FC6500.
I won’t be moving my lights but rather using a Quantum Par meter to get light levels and adjust dimming accordingly since dimming LED does not change spectrum it seems pointless to move the light up or down.
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How do you like that 600R? That was the light I was going to get, but settled on the 350R due to tent size (3x3). Figured it would have been major overkill to throw the 600 in there and not worth the $$$.
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Performed fantastic in my 4x4
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It’s hard to understand when going from HID to LED, but with modern LEDs, wattage is damn near irrelevant. PAR measured as PPFD is a much MUCH better way of evaluating what your plant is experiencing.
After they put out their second set of true leaves, seedlings can take full sunlight levels of PAR. As long as your environment is on point and can support your garden’s needs, cannabis is nearly unique among plants in that its growth rate scales perfectly with increased light from 100 par all the way up to 2000 par (noonday sun on June 21 at a mile high in the western US).
Bugbee noted in a recent video that ramping lighting slowly is a waste of time - in the lab, cannabis plants recover from drastic changes in light intensity in less than 24hrs, with many varieties never skipping a beat. So, if you see a negative reaction from drastically increasing light, it’s because something in your environment isn’t optimal.
Obviously most of us have grows that aren’t perfect lab conditions, but still, in a production environment there’s no benefit to babying them. If they can take 1000ppfd when they’re 2wks old and they grow twice as fast as if you gave them 500ppfd, in a production environment you only benefit by pushing them.
If you’re not dimming, you’re just wasting energy.
Full disclosure: I don’t exist in a production environment, and often I need to take my foot off the gas because of timelines and life events. Like, right now I have my clones under about 75ppfd and they’re in cold temps (60F-70F) cuz I want them to basically go into hibernation (but not die) for the next three or four weeks.
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Even pushing tons of CO2 I have a hard time with that. There is such a thing as too much light and it will negatively affect your plants. 1000 PPFD at 2 weeks seems way over the top to me. Than again, I am not an expert.
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Story of the last few months for me.
Not sure I’m following based on the other info you provided. Are you saying to hit them heavy with light, or not?
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I got a placebo co2 bucket in my tents. How many ppfds of ram does that give me? Do I need Nos?
I believe its because you can dim and move them closer and get the same amount of energy to the plants since the spectrum doesnt change. Assuming you got good light spread/coverage. Maybe something else as well that Im missing but that is a way to waste energy by not dimming.
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Exactly as SOLGarion said, putting the lights close to your plants and then dimming down so that the plants see the same intensity of light saves you energy. That’s one of the several reasons why why wattage is irrelevant when using modern LEDs.
If you want an explanation as to why or how this works, look up the inverse square law of light. But you can trust that it does work.
As for the more general thought of “should I slam my plants with max light?” it’s more a question of your system and growing skill. If your system is lab conditions and you’re providing all the 8 inputs plants need, and you’re providing them in a scalable manner where the plant can go as fast or slow as it wants based on all those 8 inputs never being out of balance, then yes, you can give them max light and they will not get hurt.
In the real world where most of us live, things aren’t quite so ideal. In that case, 500PPFD is fine for veg and 1000PPFD is fine for flower, but you’ll generally see fine results in the range of 200 - 700 ppfd for veg and 500 - 1300 ppfd for flower as long as your gardening skill (and all the other inputs your plants need) are on point.
Plus, this is all theorycrafting. You still gotta grow the plants. 
They’ll tell you what they need if you listen closely enough!
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Thanks nube 
. Trying to apply the KISS principle as much as I can. Info overload these days with growing trees 
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This app works alright haven’t had any light stress issues since using it, apparently the iPhone version is way more accurate, on par with an apogee meter(no pun intended)https://play.google.com/store/apps/details?id=com.homestudio.ppfdmeter
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Giving this a shot. Thanks man!
Wondering if the app has had an update.
I’ve tried it with the paper over the lenses, and a message appears saying "diffuser detected please remove diffuser ".
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Weird since it apparently makes it more accurate but maybe not. Who know with software wizardry.
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I think another good thing to mention on this topic is DLI (Daily Lightiny Integral) for different stages of the grow, seedlings, veg and flower will all require different levels of DLI.
I am using the free version, so maybe if I had the pro and calibrated it it would need the filter…(?)
I dont have a par meter, of course or why use the app except to test accuracy then, but I do have a lux meter to calibrate it with. Since it does the same sort of conversion the “premium” lux ones do to estimate par every bit of accuracy helps I guess.