Over watering in flood and drain tables?

Gquebed

Gquebed

Well-Known Member
So in my first hydro run i suffered some leaf tip curl, but i chalked it up to over feeding, especially N. I also had some other probs...

Anyway, this 2nd run is off to a way better start, but ive got the leaf curl again. i know its not over feeding or too much N this time. My ppms have only been 300 this 1st week, with way less N. In fact, i know i have to bump it up because the new leaves are much too light green.

So the leaf tip curl must be from over watering???
I flood every 4 hours for 15 mins. The tables drain in 6 mins. Plants are in clay pebbles, COB lighting, 83f and 45% rh.

If not over watering then what?
 

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redi jedi

redi jedi

Well-Known Member
Gquebed said:
So in my first hydro run i suffered some leaf tip curl, but i chalked it up to over feeding, especially N. I also had some other probs...

Anyway, this 2nd run is off to a way better start, but ive got the leaf curl again. i know its not over feeding or too much N this time. My ppms have only been 300 this 1st week, with way less N. In fact, i know i have to bump it up because the new leaves are much too light green.

So the leaf tip curl must be from over watering???
I flood every 4 hours for 15 mins. The tables drain in 6 mins. Plants are in clay pebbles, COB lighting, 83f and 45% rh.

If not over watering then what?
Click to expand...
Bare root clones in pellets or are your using rockwool too?

Lighting might be too intense also.
 
Gquebed

Gquebed

Well-Known Member
redi jedi said:
Bare root clones in pellets or are your using rockwool too?

Lighting might be too intense also.
Click to expand...
No rockwool for me. That stuff has only ever caused me major grief. So clones right into the pellets.

Light intensity would cause this? Really?

In got the cobs about 35 inches above and dimmed right down.... i got 2/3s on the dial left if i want to turn them up... but they are still pretty bright. Maybe raise them a bit? I guess...

Just out of curiosity, how would the light intensity cause the curling/clawing?
 
Logan Burke

Logan Burke

Well-Known Member
Everything ok with the PH of the water, no sudden drops lately? I've only ever done dwc, but with any type of grow ph is important and can imbalance nutes. Is your ph tester calibrated and all? I'm not sure if an out of range ph would cause that or not, but I thought it was worth adding in the thread.
 
A

Aqua Man

Well-Known Member
Looks more like under watering to me and you have some nutrient uptake issues. What is your PH. You need to up that humidity to 60%ish in those temps.

Pic of the roots might help also
 
Gquebed

Gquebed

Well-Known Member
Logan Burke said:
Everything ok with the PH of the water, no sudden drops lately? I've only ever done dwc, but with any type of grow ph is important and can imbalance nutes. Is your ph tester calibrated and all? I'm not sure if an out of range ph would cause that or not, but I thought it was worth adding in the thread.
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All good on pH and calibration. Spot on.
Thats what got me scratching my head...

The water temp got a bit high though at one point. Up to 76. But i got on that quick with a res chiller. But the curling started before that.
Hmmm....
 
Gquebed

Gquebed

Well-Known Member
Aqua Man said:
Looks more like under watering to me and you have some nutrient uptake issues. What is your PH. You need to up that humidity to 60%ish in those temps.

Pic of the roots might help also
Click to expand...
I forgot... under watering can look just like over watering. Good point.
Ph is all spot on.

The nute issue was from when the temp was too low. They just werent transpiring enough and didnt take nutes up. Soon as i bumped up the temp that changed in a hurry. Theyre greening up now.

RH could be a prob. Its so dry here getting it up is near impossible. Once they get bigger that will change but for now best i can do is a steady 45.
 
A

Aqua Man

Well-Known Member
Gquebed said:
I forgot... under watering can look just like over watering. Good point.
Ph is all spot on.

The nute issue was from when the temp was too low. They just werent transpiring enough and didnt take nutes up. Soon as i bumped up the temp that changed in a hurry. Theyre greening up now.

RH could be a prob. Its so dry here getting it up is near impossible. Once they get bigger that will change but for now best i can do is a steady 45.
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I would drop the temps a bit to compensate for low humidity maybe 75F. They probably look under watered because the increased VPD with a higher temp and lower humidity makes them drink a lot more. So I would say finding that happy spot of flooding a bit more often and lowering the temps bit would be your best bet. I would make small changes to each working towards it until you find that sweet spot.
 
Logan Burke

Logan Burke

Well-Known Member
Aqua Man said:
I would drop the temps a bit to compensate for low humidity maybe 75F. They probably look under watered because the increased VPD with a higher temp and lower humidity makes them drink a lot more. So I would say finding that happy spot of flooding a bit more often and lowering the temps bit would be your best bet. I would make small changes to each working towards it until you find that sweet spot.
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I must say this sounds like a pretty good answer. Maybe it is, maybe it isn't, but at the very least I'd follow this advice and watch for improvement. Particularly in hydroponics, RH and VPD becomes a bigger deal because of your plant's ability to basically chug nutrient rich water at slower or faster rates based on the humidity and temps. So for someone else, with 75F and 50% humidity, running the ppm's you run may be no problem. But running them in your warmer and dryer air, may burn the plants up or give them a N tox look just as yours.
 
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A

Aqua Man

Well-Known Member
Logan Burke said:
I must say this sounds like a pretty good answer. Maybe it is, maybe it isn't, but at the very least I'd follow this advice and watch for improvement. Particularly in hydroponics, RH and VPD becomes a bigger deal because of your plant's ability to basically chug nutrient rich water at slower or faster rates based on the humidity and temps. So for someone else, with 75F and 50% humidity, running the ppm's you run may be no problem. But running them in your warmer and dryer air, may burn my plants up or give them a N tox look just as yours.
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Yeah but I also think they are not getting enough water. Try flooding every 3 hours and see how that goes. Its only clay pebbles so it drains fast and with those temps I think your drying out your media to fast also add the VPD issue to this and it make sense to me from what i see in the pics. I'm seeing what I feel are deficiencies and under watering symptoms. Some micro deficiencies will also give symptoms that are similar to N tox. Lowering the temps a little and increasing the flood frequency should show positive signs pretty quickly. Like most issues the affected leaves won't get much better if at all but pay attention to new growth.
 
Gquebed

Gquebed

Well-Known Member
Aqua Man said:
I would drop the temps a bit to compensate for low humidity maybe 75F. They probably look under watered because the increased VPD with a higher temp and lower humidity makes them drink a lot more. So I would say finding that happy spot of flooding a bit more often and lowering the temps bit would be your best bet. I would make small changes to each working towards it until you find that sweet spot.
Click to expand...
Remember i am growing with COBS. So i have to ask... is the advice you are giving COB specific?
From what i have been told by COB guys is that the lack of IR requires warmer temps for proper transpiration. So while 83f might seem a lot too high for HID guys, its supposed to be the sweet spot for COB growing.

Just asking, to be sure. After all, bumping up the temp did get the plants going pretty good.

I used to be an HID guy and it killed me to take temps up to 79/80...never mind 83ish...lol
 
A

Aqua Man

Well-Known Member
Gquebed said:
Remember i am growing with COBS. So i have to ask... is the advice you are giving COB specific?
From what i have been told by COB guys is that the lack of IR requires warmer temps for proper transpiration. So while 83f might seem a lot too high for HID guys, its supposed to be the sweet spot for COB growing.

Just asking, to be sure. After all, bumping up the temp did get the plants going pretty good.
Click to expand...
You absolutely right. I grow with an HLG-600 like you no IR. So your leaf temps will prob sit close to 5-6F cooler. But I don't feel you have the humidity to grow with optimum leaf temps (75F) and you may be a little higher than necessary to start with to achieve that (During Veg I sit at 80F and my leaf temps are 75F but things like fans etc. can affect leaf temps). I mean not over the top high so you could just try increasing the watering frequency first and a bit higher temp like 78-79 to put ya on the edge but i think 83 is just a bit too much with your RH. You will see better growth with a good VPD then with a higher temp of a few degrees and and less optimal VPD. I mean THB i think the biggest factor is you need to water more often.

Grab something like this if you want to get really dialed in on VPD:
https://www.amazon.com/Etekcity-Lasergrip-1080-Non-Contact-Thermometer/dp/B00DMI632G/ref=sr_1_3?keywords=IR+thermometer&qid=1558393091&s=gateway&sr=8-3

Then go here and copy the instructions for VPD calculator:
https://www.questclimate.com/vapor-pressure-deficit-indoor-growing-part-3-different-stages-vpd/

VPD for stages of growth: Veg 0.8-1.1 Early flower 1-1.4 Late flower 1.3-1.5

But the most important thing is to get them a bit more water.
 
ttystikk

ttystikk

Well-Known Member
Gquebed said:
Remember i am growing with COBS. So i have to ask... is the advice you are giving COB specific?
From what i have been told by COB guys is that the lack of IR requires warmer temps for proper transpiration. So while 83f might seem a lot too high for HID guys, its supposed to be the sweet spot for COB growing.

Just asking, to be sure. After all, bumping up the temp did get the plants going pretty good.

I used to be an HID guy and it killed me to take temps up to 79/80...never mind 83ish...lol
Click to expand...
Keep your temps around 85F for LED grows.
 
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