Droopy leaves after some hours of light

Hello,
i grow hydro using rotating sprinklers for seedlings and bubblers for plants over 2 weeks old.

So when i use rotating sprinklers, the light is 2 fluoros cfl and i have no problem.

After 2 weeks or so, i change the plants for the production tent where i let them 2 more weeks under 18/6 of lights, using DWC technic.
There is plenty of air, good air stones, very good PH, good water temp and low EC. There is a fan and an exhaust.
The light in this tent is LED's, High power COB's that gave very good results in the past.

The problem is that after the change to bubbler, after 12 hours of light, the leaves are droopy as if they did not like the light, and they recover after 6 hours of night.
And this is every day, they are not happy at the end of the day and recover at night.

I changed for new led's, i thought it was because of old led's, but the problem is the same, it does not fix the problem.

The plant's thrieve anyway but as the plants are not happy, i'm not happy either.

Do someone have an idea ?

I've been growing this way for maybe 15 years, and never had this kind of problem.

Maybe in the past your lights were keeping them warmer?

Your issue is likely that the plants have reached their DLI, or Daily Light Integral, which is when they’ve received all the light they need for the day. They then droop their leaves for less light absorption area available. This would be especially true using new powerful COB LEDs...Even more so if using the condensed style COBs, which penetrate further than the quantum board or strip style LEDs.

I wouldn’t drop the hours of light they get, obviously, because then they would flower. Instead, you could turn down the intensity of your light, if you have a dimmer. If you don’t have a dimmer, try raising the lights for less daily intensity.

Hope this helps. Let us know if you try and see any difference.

Medicine said:

Your issue is likely that the plants have reached their DLI, or Daily Light Integral, which is when they’ve received all the light they need for the day. They then droop their leaves for less light absorption area available. This would be especially true using new powerful COB LEDs...Even more so if using the condensed style COBs, which penetrate further than the quantum board or strip style LEDs.

I wouldn’t drop the hours of light they get, obviously, because then they would flower. Instead, you could turn down the intensity of your light, if you have a dimmer. If you don’t have a dimmer, try raising the lights for less daily intensity.

Hope this helps. Let us know if you try and see any difference.

Click to expand...

I did not know this fact, thanks.

The internode is very short, never seen so short, now there are in flower and they don't stretch. They stay fat !

Sign said:

Maybe in the past your lights were keeping them warmer?

Click to expand...

You were right !

The problem is due to low temp. It seems that i did not try my leds in winter.

So i put a 400W HPS and the plants like it better.

I think that it's fixed. I don't anderstand why they grew well under fluoros as it's quite cold also...

Thanks anyway ...

I began again a new crop with 2 weeks seedlings.
I put them under High power led cobs, 60 watts each one, and i have 5 of them, so 300W total.

And i've got the same problem, droopy leaves at the end of the day.
So i put the lightning far from the canopy to see improvement or no.

Last crop i put a 400W HPS and the plants liked it, but i think that HPS gives less light than high power leds do.