Plants sagging only at the end of light cycle in veg, before and after pics.

So i'm having a wee issue and not sure if its a major problem but it seems they are happy when the lights first turn on for the first 7hours they seem to be okay, i check them in the morning when i wake up a couple hours before lights off and 2 of them are sagging.

400w MH @ 18 inches away.
Temp is around 77-85 lights on and 60-65 lights off.
Humidity is around 40 on and 70 off.
I have 2 small fans running between the lights and the plants (the leaves dance a little bit with this).
Also have 180cfm fan with filter etc running with passive intake so plenty of air exchange.

I did lower my lights to 14 inches the other day and they showed signs of heat stress so i raised them back to 18 which they were originally at.
First picture shows just as the lights come on...as you can see the plant on the left doesn't get affected at all, it's mainly the middle and right hand plant.

Side advice -

*Get meters out of the light, they heat up and give wrong readings.

*Wind bad air exchange good, you should be fine with just the 180cfm extraction, certainly it exhausts more heat than the light makes.

*Plants shunning the light is from not enough nutrients or over transpiration.

They shouldnt wilt, i might say overwatering but thats a lot worse generally.

Good luck

Kingrow1 said:

Side advice -

*Get meters out of the light, they heat up and give wrong readings.

*Wind bad air exchange good, you should be fine with just the 180cfm extraction, certainly it exhausts more heat than the light makes.

*Plants shunning the light is from not enough nutrients or over transpiration.

They shouldnt wilt, i might say overwatering but thats a lot worse generally.

Good luck

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I have a wee "Probe" thats tucked up in the canopy under the leaves so that gives me a true reading, which is the lower number on the temp gauge.
The area is only 2x4x6ft so thats more than enough air exchange
I fed with nutrients just 3 days ago and it was only half strength.
I could've possibly over watered a little as i thought they were thirsty when they started wilting but they have excellent drainage with a lot of perlite.

Is this going to affect my yield if i can't get it sorted or will they be fine doing what they're doing?
Switched the middle plant and left hand plant to see if it makes any difference.
I think i need the fan blowing over the top of them and making them move otherwise it'll get too hot won't it? Could that be causing problems with making the leaves move.

That famous droop looks like a watering issue to me. Finger down one knuckle, if it’s dry, water!!

Fullscan19 said:

That famous droop looks like a watering issue to me. Finger down one knuckle, if it’s dry, water!!

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I know, that's what it looks like to me, but it happens no matter if they've been watered or not.
I tend to pick up the containers and see how heavy they are.
The top inch is cold and a little moist, but i don't think they need water yet as they're heavy. and only happening to 2 plants.

You know it could be too much light also, happened on my last grow. I had a 300 on the left with one plant and a 450 blurple on the right with two. Plant on the left was awesome, the two on the right looked like they had an extra chromosome, scraggaly ass pistils and completely folded/withered leaves.

Swapped out the 450 for another 300 and centered the lights evenly between the 3. within 36 hours the two plants on the right perked up and were shitting out trichomes and the leaves looked fantastic. These plants are truly resilient.

Raise lights to 24 or dim them. Within 48 hours you’ll know if this was the problem.

EDIT - now that I reread your post, they look alive at the START of the lights because they had all that night time to recover.

Heat stress my dude.

Fullscan19 said:

You know it could be too much light also, happened on my last grow. I had a 300 on the left with one plant and a 450 blurple on the right with two. Plant on the left was awesome, the two on the right looked like they had an extra chromosome, scraggaly ass pistils and completely folded/withered leaves.

Swapped out the 450 for another 300 and centered the lights evenly between the 3. within 36 hours the two plants on the right perked up and were shitting out trichomes and the leaves looked fantastic. These plants are truly resilient.

Raise lights to 24 or dim them. Within 48 hours you’ll know if this was the problem.

EDIT - now that I reread your post, they look alive at the START of the lights because they had all that night time to recover.

Heat stress my dude.

Click to expand...

Yeah dude, the thing thats fucked is that me lowering the lights to 14inches made them do this, so i raised them back to 18inches and thought that'll fix it but they're still doing it now, Nothings changed and they've been awesome up until i lowered the lights 3-4 days ago that triggered this?
Heat in the grow room hasn't changed at all.
Think i should raise the lights a couple inches to 20?

Hell yeah! Even 24 man! Just for a couple days, think of it like they have a cold. After they show signs of life, slowly lower an inch by the day. I’ve never gone less than 18” with LEDs personally.

Fullscan19 said:

Hell yeah! Even 24 man! Just for a couple days, think of it like they have a cold. After they show signs of life, slowly lower an inch by the day. I’ve never gone less than 18” with LEDs personally.

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24c is 75 Fahrenheit which is perfect isn't it?
Yeah, ill raise it a bit and see if it makes a difference, if it does then ill lower it slowly until it starts showing signs again and back it off.
Thing is they'll be back to normal after their dark period which is in 15min.. after 6 hours of dark they look good as again.
Cheers man.

How many ml of water do you give them when feeding?

Looks like they should be taking about 500ml.

Daveindiego said:

How many ml of water do you give them when feeding?

Looks like they should be taking about 500ml.

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They're in 6l pots, they get almost a 1000mls each, which creates a tiny bit of run off.
There's a shit load of perlite, like 40% so drainage is great.

goatlicker said:

They're in 6l pots, they get almost a 1000mls each, which creates a tiny bit of run off.
There's a shit load of perlite, like 40% so drainage is great.

Click to expand...

I dunno, seems like a lot.

Try dialing back to 750ml next feeding?

Daveindiego said:

I dunno, seems like a lot.

Try dialing back to 750ml next feeding?

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Yeap, willing to try anything at this stage.
I've raised the lights to 22inch and will see if they recover and slowly drop it back to 18.

Kingrow1 said:

Side advice -

*Get meters out of the light, they heat up and give wrong readings.

*Wind bad air exchange good, you should be fine with just the 180cfm extraction, certainly it exhausts more heat than the light makes.

*Plants shunning the light is from not enough nutrients or over transpiration.

They shouldnt wilt, i might say overwatering but thats a lot worse generally.

Good luck

Click to expand...

Daveindiego said:

I dunno, seems like a lot.

Try dialing back to 750ml next feeding?

Click to expand...

Fullscan19 said:

Hell yeah! Even 24 man! Just for a couple days, think of it like they have a cold. After they show signs of life, slowly lower an inch by the day. I’ve never gone less than 18” with LEDs personally.

Click to expand...

So these are new pictures, 10 minutes after lights turned on, swapped the middle one and left one around to try avoid more heat in the center.

Report back in 24 hours I’m stoked for results!!

probably just light too close 400w MH @ 18 inches away id keep it 28 or 32 depending how much node spacing you want
i wouldn't keep my lights 18inch even in flower
pots are probably getting too hot

Fullscan19 said:

Report back in 24 hours I’m stoked for results!!

Click to expand...

Kipn said:

probably just light too close 400w MH @ 18 inches away id keep it 28 or 32 depending how much node spacing you want
i wouldn't keep my lights 18inch even in flower
pots are probably getting too hot

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Not good news, still doing it even with the plant moved further away and the light raised.
I don't understand how they were all good for 2 weeks before this @ 18 inches then its doing this ONLY at the end of the light cycle.
First 6-8 hours of lights on they're sweet, then i go to bed and wake up and shes like this.

Why dont u raise the light untill u notive stretching, than lower it a couple inches from there. 18 inches seems really close, this is a 5 week old at around 4 feet from the light 420w hps/led in a 2x4x6. My lights hang around 1.5 feet down from the top and the plants are flat on the floor. Atleast 3.5 feet seperation and still zero stretch.

Try at 24 man! They need to recover!! But honestly they don’t look that bad, it’s gonna be something simple, don’t give up

grilledcheese101 said:

Why dont u raise the light untill u notive stretching, than lower it a couple inches from there. 18 inches seems really close, this is a 5 week old at around 4 feet from the light 420w hps/led in a 2x4x6. My lights hang around 1.5 feet down from the top and the plants are flat on the floor. Atleast 3.5 feet seperation and still zero stretch.

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I had it up to 22inches since the lights turned on but that's still happening.
The big one is 4 weeks today from when it sprouted and rest are 3 weeks 1 day.
1. Why is the now middle plant unaffected by this?
2. Why has it only started now when they've been fine for 2 weeks at 18 inches?
3. Could it still be recovering from the 14inch away light and may take a few days?

I'll raise the light yet again to 25 inches and see if that makes a difference.
Quite frustrating when at the start of their light cycle they look amazing and i wake up and check and they look sad

Edit.

Fullscan19 said:

Try at 24 man! They need to recover!! But honestly they don’t look that bad, it’s gonna be something simple, don’t give up

Click to expand...

Yeap, i've just raised it to 25 inches now.
I was thinking they might need time to recover from the light being at 14 inches...