Leaf Burn when switching to Flower

kunkgrow

Active Member
Hey guys˜!
This is the 3rd time I have the same issue.
Can't point the problem.

The veg time is awesome, quick growth, no burns, amazing leafs:

As soon as 12/12 starts, leafs begin to burn, without any environmental changes:

Than goes downhill fast:

EC is 1.2, PH 5.8, straight coco.
Temps 27C, RH 70%, good VPD.

Jacks 321 with RO water.

The lighting is a custom DIY panel with 2x Phantom Boards @ 2 amps, 10x Clu048 1212 cobs 97CRI @ 1 amp.
Everything dimmed down to around 30.000 lux.
Sealed room with CO2 only dispensing enough to maintain around 500ppm, not boosting. Exhausting 15min every 2 hours.

I don't know what to do...
 

Attachments

CannaCountry

Well-Known Member
What ratio of the Jack's 3 2 1 formula are you using? RO water is sometimes difficult to maintain in terms of a constant pH; are you sure your reservoir (I'm assuming you're pumping from a reservoir for your drip irrigation?) is maintaining it's pH through out the life of your feed? I use Jacks as well, though using tap and I've never seen this without something else being way out of whack.
 

kunkgrow

Active Member
What ratio of the Jack's 3 2 1 formula are you using? RO water is sometimes difficult to maintain in terms of a constant pH; are you sure your reservoir (I'm assuming you're pumping from a reservoir for your drip irrigation?) is maintaining it's pH through out the life of your feed? I use Jacks as well, though using tap and I've never seen this without something else being way out of whack.
Exactly 3 hydro, 2 cal, 1 mag.
PH is rock solid, I have a webcam looking into the plants on a position that the bluelab monitor appears, and if I time lapse through the recordings it only rises because of the automatic top off. from 5.5 (when newly reset) to 6.0 as RO is added back.
My range is set to 1.2 EC, as soon as the reservoir gets diluted to 1.0, a set of pre programmed peristaltic valves kick in adding back each fertilizer using the 3 2 1 ratio to get it back up to 1.2 again.
Then once a week I go in, flush the plants and reset the reservoir clean and start over.

The runoff PH is also not too far. Feed 5.8 in, runoff is 6.0. EC IN 1.2, EC OUT 1.4

Maybe there is something to do with my coco locking out magnesium due to potassium imbalance?

I'm clueless
 

a mongo frog

Well-Known Member
Hey guys˜!
This is the 3rd time I have the same issue.
Can't point the problem.

The veg time is awesome, quick growth, no burns, amazing leafs:

As soon as 12/12 starts, leafs begin to burn, without any environmental changes:

Than goes downhill fast:

EC is 1.2, PH 5.8, straight coco.
Temps 27C, RH 70%, good VPD.

Jacks 321 with RO water.

The lighting is a custom DIY panel with 2x Phantom Boards @ 2 amps, 10x Clu048 1212 cobs 97CRI @ 1 amp.
Everything dimmed down to around 30.000 lux.
Sealed room with CO2 only dispensing enough to maintain around 500ppm, not boosting. Exhausting 15min every 2 hours.

I don't know what to do...
Have you grown under another light before? Just asking to see if you have seen this before under hps, because i have under hps seen this. Looks like floro burn. What are the lamp heights?
 

kunkgrow

Active Member
Have you grown under another light before? Just asking to see if you have seen this before under hps, because i have under hps seen this. Looks like floro burn. What are the lamp heights?
Actually I did try switching to HPS for a few days to see if it would stop but it never did. It was much harder to control the envirnment (temperature and RH) and the leaf necrosis progressed jst as much.

The light is dimmed to about 200w from the wall height 70cm above canopy.
 

nmibud

Well-Known Member
It looks like light burn from your leds,I had the same thing when running the higher cri lights.I had to dim it down.
 

CannaCountry

Well-Known Member
Exactly 3 hydro, 2 cal, 1 mag.
PH is rock solid, I have a webcam looking into the plants on a position that the bluelab monitor appears, and if I time lapse through the recordings it only rises because of the automatic top off. from 5.5 (when newly reset) to 6.0 as RO is added back.
My range is set to 1.2 EC, as soon as the reservoir gets diluted to 1.0, a set of pre programmed peristaltic valves kick in adding back each fertilizer using the 3 2 1 ratio to get it back up to 1.2 again.
Then once a week I go in, flush the plants and reset the reservoir clean and start over.

The runoff PH is also not too far. Feed 5.8 in, runoff is 6.0. EC IN 1.2, EC OUT 1.4

Maybe there is something to do with my coco locking out magnesium due to potassium imbalance?

I'm clueless

So you're recycling your feed runoff back into your reservoir?... and once this happens your system automatically adjusts the feed back to your starting point EC by adding back your 3 2 1 ratio? If I'm reading that correctly, how does your system know which elements to add back? In other words, if your plants are pulling high amounts of potassium, which is going to lower your EC, how does the system know to put back the potassium but not the other things which the plant may or may not be taking in? And while I'm not a proponent of testing run off, it would stand out to me as odd that my EC was higher coming out of the plants than going in. The sound of your system is pretty intriguing though.
 

kunkgrow

Active Member
So you're recycling your feed runoff back into your reservoir?... and once this happens your system automatically adjusts the feed back to your starting point EC by adding back your 3 2 1 ratio? If I'm reading that correctly, how does your system know which elements to add back? In other words, if your plants are pulling high amounts of potassium, which is going to lower your EC, how does the system know to put back the potassium but not the other things which the plant may or may not be taking in? And while I'm not a proponent of testing run off, it would stand out to me as odd that my EC was higher coming out of the plants than going in. The sound of your system is pretty intriguing though.
Its drain to waste so the balance on the reservoir is never changed.
 

kunkgrow

Active Member
I invested blindly on 97 cri cobs thinking hey it’s a fuller spectrum what could go wrong?
Could’ve saved couple bucks by going with tried and tested 80
 

TacoMac

Well-Known Member
Too hot and too humid. Look how the leaf edges are curling up into a cup.

Your light is too close. Note how you're only getting the cupping and burning right in the middle. The outer ends of your grow on both sides look fine.

You'd probably be better served with two lower power lights spread equally over that sized grow than one hot one. You'd have far more control that way.
 

kunkgrow

Active Member
The light panel is very spread out.
The strain is alien rift which is know for this leaf curling appearance
However as I mentioned just before I do think there might be something related to the lighting
 

nmibud

Well-Known Member
I built a 4 cob array with citizen clu048 1818 3000k 90cri.It caused burning like you are seeing,it was the same time I switched to hempy.I had a hard time figuring It out.I have since switched to strips.
 
Top