can't unscrew. This is a sealed unit. I'll see how raising the lights up a bit helps. Like I said, these are bright lights.

On my lights, whatever is in the direct middle of where the light is pointed gets the most light. That of course makes sense but I think the effect is much more when using LEDs because the light is more directional. A fan blowing the leaves around may help along with blowing or moving the lights to get them to point in slightly different directions.

If you have a smartphone, get a light meter app and check the LUX.

Actually I do have a Lux meter. At 6" from source it reads 95,000 ... at 18" 37,500 and at 36" 25,000. That's a lot of Lux for a 300 watt LED.

My 200k lux meter hasn't arrived yet but using my phone I get about 25,000 lux at 18".

My banana pepper and cayenne pepper sprouts are 30" away at around 9k lux. No blackening lol.

Incidentally, I've read that \photosynthesis plateaus at around 5-10k LED lux, 10-20k sun lux.

Can you recommend a physical lux meter or iPhone lux meter app that works well? I tried a half dozen of the free apps but they were all pretty poor.

Eh, direct bright summer sunshine should be around 100,000 lux. Even when it comes in through my window it maxes out my crappy phone app at 67k+. Once my legit lux meter arrives I can measure it better.

I use a LX1010BS meter ... http://www.amazon.com/Dr-Meter%C2%AE-Light-LX1010BS-display-Luxmeter/dp/B004KP8RE2 ... btw way I checked outside and it was 107,000 with no clouds so I stand corrected. I have to stop believing everything what I read on line ....

dba1954,

What was the solution? Did you just raise the light and it
was fixed?

hard to tell ... I did raise it a lot... to 36" but will not know the results for another week. The tomatoes and peppers aren't getting leggy but still look a bit upset. I plan to grow a jalapenos and habanero indoors over the summer and winter to see how it works out. I will post progress.

raising the light to 36" did just fine. very healthy plants. Growing Habs, cauliflower , eggplant and sweet peppers indoors . All look superb.

Generally it takes less light from an LED grow lamp to grow plants than it does from other types of grow lamps. Many people using the new LED grow lamps may not realize that their plants do not need so much light. LED lamps can tend to be more directional and send the light down in a more focused direction, so that is another factor. In the cases where LED light does burn leaves, it is from the BLUE wavelength LEDs, not the red.

So long as you are using the proper wattage, the light is evenly distributed, LED light is much less likely to burn leaves than the light from fluorescent tubes. But because of the nature of LED grow lights, people often use too much of it. First, LED uses a lower wattage because it is much more efficient, and second, LED grow lights appear to put out a lot less light than they actually do because the human eye has a much lower sensitivity to the short blue and very long red wavelengths which the LED lamp emits. You simply can't see all the light it is giving off.