Leds causing stress

RedBeardy5

Active member

• Feb 13, 2021

• #1

So I bought a hlg650r and everytime I put the plants under it they turn pale and droop. I tried hanging them 3ft above the canopy on low and everytime they droop. I then put them under my hps light and they perk back up. Nothing I try seems to work. Does anybody else have this problem? I'm thinking the red is stressing them, but then why are they recovering under hid lights.

 

Hold Your Fire

Finding my way back home

Veteran

• Feb 13, 2021

• #2

I have the same experience.

From what I have cobbled together, under LED's plants like it warmer and more nutes, maybe just calcium is often required.

My plants went to crap under my spider Farmer and recovered fully under hid's

My lights on temp right now in the middle of winter is 68-72F.

Lights off 62-63. We have had night time temps -5 to 10 above lately and I'm in the basement.

LED is now back in the box until I can get temps to 80, and figure out what else might be required.

 

U

unregistered190

Senior

Veteran

• Feb 14, 2021

• #3

I believe some plants are more sensitive than others to the brightness or spectrum of LEDs, has it been your experience with multiple strains or just one?

I have been running LEDs in small tents for years now and haven’t really had any issues I would attribute directly to the lights.

Maybe dim them down some or raise them higher above the canopy at first.

You will get them figured out and once you do you probably won’t look back

 

RedBeardy5

Active member

• Feb 14, 2021

• #4

Thats intresting. I did notice they do better when its around 85. I just harvested so my rooms are colder. Ill keep everyone updated.

 

Koondense

Well-known member

Veteran

• Feb 14, 2021

• #5

There is almost no infrared in the leds so keep the space hotter compared to hps, the plants will love it.


Cheers

 

f-e

Well-known member

Mentor

Veteran

• Feb 14, 2021

• #6

Might be Mg. It's a common deficiency with LEDs and is necessary to form green. A subtle thinning of the leaf tips with a tendency to turn to the side is a good sign of this. Not twisting, they remain flat and healthy looking, but are not totally straight. Having the last 20mm veering off to the side just 10 degrees perhaps. Its the best sign to look for as nothing else does it.

 

gatts

Active member

• Feb 14, 2021

• #7

Def think its variant dependent too. My Nice Chunk looked a bit stressed, the first cut of her performed way better. 2 Skunks looked stressed but the Skywalker was fine. Same tent, germ times and nutes.
Running 2xSP250's in a 4x4 veg. Had to lift them to 1m of the canopy, the girls love it.

 

f-e

Well-known member

Mentor

Veteran

• Feb 14, 2021

• #8

There is no doubt it's strain dependent and that they can become accustomed to it over time.

It won't be long until we are buying seeds from breeders that work under LED's and as such produce the goods we need. Making HID growers do the moaning

 

Muleskinner

Active member

Veteran

• Feb 18, 2021

• #9

IMO this is probably simple light shock. With LED's it can be difficult to judge the brightness on the canopy without a PAR meter. Most LED's provide far more blue & red wavelengths than HID. The brightness may look similar to your eyes but the plants are getting blasted.

I would allow 2-3 weeks for plants to get accustomed to the more intense LED light. Start with the light WAY far away or dim it way down. If 3 feet isn't working try 4 or 5 feet. Then increase the brightness on the canopy every few days until you're up to full power. The pro LED fixtures I was using needed the plants to start 55-60" inches away - 5 feet - but after a few weeks the tips of the plants could grow within 15 inches no problem. These were only 320 watt fixtures.

 

H

Horselover Fat

Member

Veteran

• Feb 19, 2021

• #10

I think if your plants get stressed under leds it's because they are not getting their other demands met. High light levels require other limiting factors to be met and it isn't as easy as with lower intensity. It may be that the plant's root system is not large enough or the feed isn't optimal.

 

RedBeardy5

Active member

• Feb 22, 2021

• #11

So I increased the temps to 85 and dimmed them to 20% and like clockwork they are starting to recover. I put the lights at 40% today and they drooped again. So my conclusion is the light is much more efficient that HIDs.

 

VerdantGreen

Genetics Facilitator

Boutique Breeder

Mentor

ICMag Donor

Veteran

• Feb 23, 2021

• #12

yes, you need all your ducks in a row to get your plants to handle modern LEDs, especially in veg.

Temps, soil temp, not rootbound, extra cal/mag, etc.

 

f-e

Well-known member

Mentor

Veteran

• Feb 25, 2021

• #13

I think I'm kidding myself that I can put 600w inches above a meter. Any petiole the light touches is sprayed red, while the tops of buds can refuse to go any higher. I can combat the red with crazy amounts of Mg but then I get Mg patterns on the lower leaves that are hard grainy brown. I can't balance it.

In fairness I come from GreenPower son's at 1.7umol/j that would of put maybe 1.5umol/j down on a good day(shade and age losses). The 301H is talking 3umol/j so 400w is a third more. I'm trying for double. It was never a great idea. Though a 450w run did come in 25% under target so I'm reluctant to try that again. Though I recognise I'm doing this wrong.

450w has always seemed perky. An improvement over 400w that can be seen in a day. Beyond 450 I can't say I have seen any improvement at all. Keeping in mind it's not 18" up, it's more like 8 but spread


My lights are the R-spec blend and the sodiums were top notch in award winning shades (50p shades. Pro ultra something. 8 sides..)

 

Mars Hydro Led

Grow on Earth Grow with Mars

Vendor

• Feb 25, 2021

• #14

RedBeardy5 said:

So I increased the temps to 85 and dimmed them to 20% and like clockwork they are starting to recover. I put the lights at 40% today and they drooped again. So my conclusion is the light is much more efficient that HIDs.

Click to expand...

that is a good news

 

T

Tropical Sun

Member

• Feb 28, 2021

• #15

Didn't realize led can be so fickle, sucks
to hear this!

 

Mike Litoris

Member

• Feb 28, 2021

• #16

HPS is better option.

 

Greenheart

Active member

Veteran

• Mar 5, 2021

• #17

Raising my light(s) has made all the difference.

I had 3 thirty watt led's vegging a 2' x 4' room at around 20" above the tops. I thought it was my soil. Even premixed bags wasn't helping. I reduced it to one light 40" above canopy and they are doing much better. It just blows my mind that I'm vegging that much space with so little power from so far away. Certainly glad I went with that extra ceiling height.

 

flylowgethigh

Non-growing Lurker

ICMag Donor

• Mar 6, 2021

• #18

Yeah, too hot. Me too. To get the same power at the leaf, you can lower the lights and turn them down, or raise them and turn up the power. If they are constant power, you need to find that happy height. I found that with the light higher and running at higher power, the tent would get hotter. But yeah, you can overdrive the roots ability to supply coolant I think. Then there is this humidity thing to chase.