Can LED lights burn leaves?

[IngieBee]

Some of my orchids, mostly oncidiums, are getting massive tans, weirdly, due to the setup being rather equal in light everywhere, my phals aren't getting lighter leaves and aren't changing color, as they're still deep green, almost what I consider dark green! A tall plant touches the LEDs even with no I'll effects!

I didn't think they could burn, but the discoloration to a deep solid burgandy/brown pb on my Oncidium types has me a wee bit nervous and I'd appreciate a bit of confirmation that it's not possible to burn under LEDs ?

I do have an US humidifier, so maybe they could dry my plants out without it?

I just don't see a thread on this and would appreciate knowing for sure if non-UV or IR LEDs are completely safe? Thanks!

[camille1585]

I'm not sure about burns, though think it is possible, but you can definitely give too much light even with LEDs. Red pigmentation is a good example of that. It also depends on several factors, such as the output of the lights, duration they are on, and distance from the plants.

What sort of leds do you have? Could you also post photos of the plants you are concerned about?

[Subrosa]

For sure!

[Ray]

"Burn" in leaves can be either from directly-applied heat, or that generated when the light intensity is too great - often it's a combination of both.

[IngieBee]

I will post pictures when I get back home later, thanks everyone

[Dollythehun]

Yes, where my leaves gave touched or barely touched the lights they have burned. It also depends somewhat on the plant.

[IngieBee]

I have come to the same conclusion. I'm sorry I am so late to post my picture, but this Oncidium "sweet ears" has been under Blurple lights for 3 months, and at first I thought that the purple coloration on my psuedobulbs was just fine, but the leaves have also gone, what I belive is too yellow and the purple pigmentation is getting excessive. They just don't look healthy

IMG_20190606_231032851 by ingiebee, on Flickr

So I have lifted my lights 6 inches and moved the most effected away to the darkest corners for a while. I'll have to see if this will be enough. This plant does have 2 new growths, so it should be just fine, still it's not a pretty sight (picture was taken directly from above to show all discoloration) I do have a dendrobium nobile and spectabile that arrived today, and they stand 6" from the lights from the top, because they're both very tall. However, they require a lot more light, so I'm hoping this will be all right.

However, this "burning" or over-exposure took a while, and I will remove these plants if they change color quickly.

Please let me know if any of you are growing in Blurple light and how it's going for you, especially if you've been doing so for a long while, I'm very interested! Really, this has been my worse case, and the other girls seem to be fine, even my Red Wasp and Sarry Baby, I have a miltoniopsis which was a gift from a seller, and I figured it wouldn't ever live in my area, but I'm encouraged that it seems to be laying down roots (after losing some leaves first) I'm hoping the Leca I have her in will keep her roots nice and cool, and that I can keep the room below 90 degrees through the worst of the summer. We'll see if it's enough!

[SouthPark]

If the colouration is there, and if your leaves don't go yellow and then rot etc, then that pigmentation could possibly be a good sign, rather than a bad sign. If you feel that the lights could be too close, then move them away a bit.

[Dollythehun]

You can also put the lower light plants toward the outside edges of your shelf, or raise your lights and set the higher light plants on something.

[bogdan]

LEDs can definitely burn leaves. I had a cattleya right in the lights and it now has circular dry spots where the lights almost touched it. If even Vandas can bloom under LEDs, they surely can burn an Oncidium (and yours already has an unhealthy shade of purple and yellow to it).