Leaves twisting - Roots or environmental?

[Delps8]

Nice that's a beast of a plant for sure!
one thing I have noticed on your chart is there is no distance light to plant but I noticed you was hitting near 1000ppfd @ 300w... My top Cola is quite close to the light and (aaah at this point I realised my math was wrong) I'm getting 800ppfd @ 350w. I used a app on my phone to measure ppfd though so I could be higher then I think or your lights is just more efficient. I have the mars hydro fc-e6500 which touches all the walls of the tent.

Most of the time, it's 14". I ChilLED recommends 12-24 but I plotted some data for the X3 and that looked to be the best HH.

"app on my phone" - gacck (clutches chest). I'm not a big fan of software + phone. It's a few paragraphs long (like everything else) If you can calibrate against a known good source (lux meter or PAR meter), then an app can do the trick. My preference, as a programmer of 30+ years of experience who's has tested Photone twice and how has a lux meter and a PAR meter, unless you're sure that your app is correct, I'd go with the Uni-T Bluetooth. It's accurate, regardless of what model phone you have.

Lights vary in efficiency. I get 50µmol or so more from my X3 Growcraft than I do from my Mars SP 3000. That's because of a different spectrum and different diodes and maybe even the driver.

Another difference, and one regarding which I just sent an email to ChilLED customer service — I have a two bar veg light from CHilLED (an "X2") and, in our email conversation, I mentioned that the X2 was giving off a lot more heat than I was getting from the X3 but it was not only more heat, it was more light. At 250 watts, the X3 was 98° - yup, barely warm to the touch. In contrast, the X2 was >110, enough that I had to leave the tent open about ½ down the front to keep temps < 80°. By adding the light bar in the middle, I'll be able to run a lower dimmer setting and generate less heat while keeping the same PPFD.

But yeah 800 is on the lower side so the foxtail look could just be genetic I'm just mor concerned about the twisting leaves. And I'm sure that when a leaf twists from light stress the whole leaf flips over but in my case it looks like the individual fingers are twisting?
But with all this information this is why I was blaming the roots but the lights was always a thought.

It is all connected but, if you're getting higher levels of light on your plant, something that's gone sideways in the root zone can impact how well the plant handles light. There was a case of a grower here on 420 who's grow could not handle > 600µmol. He eventually found that the soil at the bottom of his pot had dried and was hydrophobic. That impacted the rest of the grow significantly.

I'm seeing the tips curling a bit and they're light brown. Isn't that classic nute levels too high? I don't know much about nutes, frankly. A question - Fernandez is big on this point - often, a nutrient issue is not due to an overabundance of that chemical but is due to the wrong level of its antagonist. Or something like that, the idea, in my brain anyway, is that it's not too much of thing A it's, too little of Not(thing A).

 

[Greenvein]

Most of the time, it's 14". I ChilLED recommends 12-24 but I plotted some data for the X3 and that looked to be the best HH.

"app on my phone" - gacck (clutches chest). I'm not a big fan of software + phone. It's a few paragraphs long (like everything else) If you can calibrate against a known good source (lux meter or PAR meter), then an app can do the trick. My preference, as a programmer of 30+ years of experience who's has tested Photone twice and how has a lux meter and a PAR meter, unless you're sure that your app is correct, I'd go with the Uni-T Bluetooth. It's accurate, regardless of what model phone you have.

Lights vary in efficiency. I get 50µmol or so more from my X3 Growcraft than I do from my Mars SP 3000. That's because of a different spectrum and different diodes and maybe even the driver.

Another difference, and one regarding which I just sent an email to ChilLED customer service — I have a two bar veg light from CHilLED (an "X2") and, in our email conversation, I mentioned that the X2 was giving off a lot more heat than I was getting from the X3 but it was not only more heat, it was more light. At 250 watts, the X3 was 98° - yup, barely warm to the touch. In contrast, the X2 was >110, enough that I had to leave the tent open about ½ down the front to keep temps < 80°. By adding the light bar in the middle, I'll be able to run a lower dimmer setting and generate less heat while keeping the same PPFD.


It is all connected but, if you're getting higher levels of light on your plant, something that's gone sideways in the root zone can impact how well the plant handles light. There was a case of a grower here on 420 who's grow could not handle > 600µmol. He eventually found that the soil at the bottom of his pot had dried and was hydrophobic. That impacted the rest of the grow significantly.

I'm seeing the tips curling a bit and they're light brown. Isn't that classic nute levels too high? I don't know much about nutes, frankly. A question - Fernandez is big on this point - often, a nutrient issue is not due to an overabundance of that chemical but is due to the wrong level of its antagonist. Or something like that, the idea, in my brain anyway, is that it's not too much of thing A it's, too little of Not(thing A).

Cheers for your time and information bro I just checked out some of the uni-t equipment and they have some useful stuff but will give the light meter a try as it's not expensive

Im still pretty set on my issue being ph at the roots. I monitor my salts in and out so know I definitely don't have a build up but you could be correct on one thing as I mixed some organics in this week which most likely would have messed my ratios up and gave me some toxicity signs but all good I'm in Coco so fixed in one feed.
I'm just trying a lower pH for a few days (5.8) to see if that helps but need to give this chang a but if time to see if it works

 

[Delps8]

Cheers for your time and information bro I just checked out some of the uni-t equipment and they have some useful stuff but will give the light meter a try as it's not expensive

Good to hear. Last I checked, it was $32 delivered. That's…nothing. I've attached a PDF that I put together on Lux to PPFD conversion.
The FC-E6500 has a really nice PPFD map. There's a drop off at 6" on each side but, other than that, it's < 4%±. Wow. Anyway…
Mars has hang heights here but 100% at 16" is really close/right at too much of a good thing. The Uni-T will help get you dialed in really quickly.

Im still pretty set on my issue being ph at the roots. I monitor my salts in and out so know I definitely don't have a build up but you could be correct on one thing as I mixed some organics in this week which most likely would have messed my ratios up and gave me some toxicity signs but all good I'm in Coco so fixed in one feed.
I'm just trying a lower pH for a few days (5.8) to see if that helps but need to give this chang a but if time to see if it works

Understand about "coco fixed in one feed". That's the nice thing about hydro or coco - if we screw it up, we can fix things pretty quickly.
I hope you get it figured out.


PDF attached.

Which conversion factor to use? The only number I've seen bandied about is 0.015 and I think that's a good number for that light.

 

[Greenvein]

Good to hear. Last I checked, it was $32 delivered. That's…nothing. I've attached a PDF that I put together on Lux to PPFD conversion.
The FC-E6500 has a really nice PPFD map. There's a drop off at 6" on each side but, other than that, it's < 4%±. Wow. Anyway…
Mars has hang heights here but 100% at 16" is really close/right at too much of a good thing. The Uni-T will help get you dialed in really quickly.


Understand about "coco fixed in one feed". That's the nice thing about hydro or coco - if we screw it up, we can fix things pretty quickly.
I hope you get it figured out.


PDF attached.

Which conversion factor to use? The only number I've seen bandied about is 0.015 and I think that's a good number for that light.

Bro no idea about all this stuff.. i just tried to use this calculator on a website but don't think its right?

I got my lights down at the moment but these are the app reading and lux meter readings.

Cheers

 

[Delps8]

Bro no idea about all this stuff.. i just tried to use this calculator on a website but don't think its right?

I got my lights down at the moment but these are the app reading and lux meter readings.

Cheers

Thank you for posting that. You're getting results similar to mine with Photone. What phone are you using?

 

[NickHardy]

Bro no idea about all this stuff.. i just tried to use this calculator on a website but don't think its right?

I got my lights down at the moment but these are the app reading and lux meter readings.

Cheers

Hey bro - is that the one @Delps8 recommended?

I ordered one that pairs with an app - there were three choices all in Thai and its coming from China $22 though. Next weekend maybe.

Interested to the Photron app v. Pulse Pro v. The BT model thing. I’m always gonna lean to the dedicated sensor being more accurate. Be interesting to compare the three.

 

[Greenvein]

Thank you for posting that. You're getting results similar to mine with Photone. What phone are you using?

Pixel 6

 

[Greenvein]

Hey bro - is that the one @Delps8 recommended?

I ordered one that pairs with an app - there were three choices all in Thai and its coming from China $22 though. Next weekend maybe.

Interested to the Photron app v. Pulse Pro v. The BT model thing. I’m always gonna lean to the dedicated sensor being more accurate. Be interesting to compare the three.

I thought it was but I ended up with the non Bluetooth version doesn't matter as it was only to confirm my mobile app wasn't giving me wild readings

 

[NickHardy]

I thought it was but I ended up with the non Bluetooth version doesn't matter as it was only to confirm my mobile app wasn't giving me wild readings

Yeah it looks the same same as mine. I’d like to compare some. I also have a potential issue with one light, I deal factory direct with them and using a known brand to compare expected levels probably helpful. So thank you @Delps8 !

I have a great relationship with those light guys btw, its just troubleshooting some customisation.

 

[Delps8]

Pixel 6

Thank you for posting that. It helps illustrate a limitation of using a software app to determine light levels. When I tested Photone the first time, it failed to give a reading. I was testing a blurple, I used the right "diffuser", etc. Photone, on my iPhone XSMax, could not get a reading.
I tested Photone about a year later against a Growcraft X3 flower spectrum light and Photone was consistently 16% high.
I traded email with growlightmeter.com during both tests. I've been a software engineer for > 30 years, including three years for Apple, so I have some insight into the problem that they're trying to solve. It's tough because each sensor reads a little differently. If you can calibrate your device against a known good source, that helps resolve the problem of different sensors. It's easier on an iPhone because there aren't many different models and Apple tends to source high quality chips and tends to use the same brands.
If you're in the Android, it's a very different problem to solve because there are so many devices and so many sensors - that's what their programmer shared with me and I accept his point of view on that.
These are some of the reasons why I recommend a light meter over software but, as you've run into, there's some math involved!

Here's an explanation of why math is involved and how to do the math.

The Uni-T is indicating 3400 lux. Check the graphic in my PDF that shows what colors the human eye can see vs the colors of light that are in the PAR spectrum.

We're really good at seeing green but can't see much read or violet, right? Last week, there was a double rainbow here (it does rain in Southern CA!). Sure enough, the violet was really faint but the green stood out. That's just the way our eyes/brain work.

The sensor in the light meter is designed to read the spectrum that matchs the human eye so we know that it's accurate in the green part of the spectrum but not accurate when it comes to reading the red or blue ends. If we want to know (approximately) what the PPFD reading is, we need to convert lux to µmol ("micromole").

If you have a standard white LED grow light, use a conversion factor of 0.015. In the case of 3400 lumens that would be 34000*0.015 = 510µmol. There's an extra "0" in there because of how the lux meter shows the value - they drop a 0 to save space in the display.

Based on the above numbers from the phone, you're getting about 510µmol from that light. Photone is reading about 18% high. That's close to the 16% high that Photone was reading when I tested it (Growcraft flower spectrum + iPhone XSMax) and the error was consistent over all dimmer settings, as expected.

The conversion factor, 0.015, is for a standard white LED. A veg light has more blue light in it so the conversion factor is different. Likewise, a flower light, like the Growcraft or the HLG flower lights, have more red. Unless you're using one of those lights, stick with 0.015.

Or, since you've been able to calibrate Photone using the Uni-T, you keep using Photone but understanding that it's probably reading high so take the reading off of Photone and reduce what it's telling. Based on what you've posted, knock off 16% or, to make it easier, knock off 20%. That will get you in the ballpark.

"ballpark" - that's a big thing to understand. A light meter will allow a grower to set a light level that he wants the plants to have but the important thing is what the plants want so the trick is to turn up the PPFD until you're in the "high light zone", and see how the plants react.

What is the high light zone? That's my just-made-up phrase for the "light saturation point" which is 800-1000µmol for cannabis, in ambient CO2 and assuming that the other factors of the grow are optimized.

With that in mind, aim for 800µmol as a target. I start with 200µmol as seedlings, hit 400 by day 21, when I top the plants, and then ramp up as quickly as I can to the light saturation point.

If the light levels are too high, you will see "photo avoidance" - the leaves nearest the light will taco/canoe or may rotate around their petiole. If you don't watch for that and take action, the leaves will eventually be damaged. It's rare to damage your plants with too much light. Over the course of a grow, I'll probably turn it up a bit to high during early veg.

Each plant is different so, when I'm pushing light levels as high as I can, I completely expect that I'll overshoot. Not a problem - if I see that they're getting too much light, I'll drop the dimmer a bit/use my meter to drop the PPFD, and it takes 30-60 minutes for them to return to their normal shape.

 

[NickHardy]

Thank you for posting that. It helps illustrate a limitation of using a software app to determine light levels. When I tested Photone the first time, it failed to give a reading. I was testing a blurple, I used the right "diffuser", etc. Photone, on my iPhone XSMax, could not get a reading.
I tested Photone about a year later against a Growcraft X3 flower spectrum light and Photone was consistently 16% high.
I traded email with growlightmeter.com during both tests. I've been a software engineer for > 30 years, including three years for Apple, so I have some insight into the problem that they're trying to solve. It's tough because each sensor reads a little differently. If you can calibrate your device against a known good source, that helps resolve the problem of different sensors. It's easier on an iPhone because there aren't many different models and Apple tends to source high quality chips and tends to use the same brands.
If you're in the Android, it's a very different problem to solve because there are so many devices and so many sensors - that's what their programmer shared with me and I accept his point of view on that.
These are some of the reasons why I recommend a light meter over software but, as you've run into, there's some math involved!

Here's an explanation of why math is involved and how to do the math.

The Uni-T is indicating 3400 lux. Check the graphic in my PDF that shows what colors the human eye can see vs the colors of light that are in the PAR spectrum.

We're really good at seeing green but can't see much read or violet, right? Last week, there was a double rainbow here (it does rain in Southern CA!). Sure enough, the violet was really faint but the green stood out. That's just the way our eyes/brain work.

The sensor in the light meter is designed to read the spectrum that matchs the human eye so we know that it's accurate in the green part of the spectrum but not accurate when it comes to reading the red or blue ends. If we want to know (approximately) what the PPFD reading is, we need to convert lux to µmol ("micromole").

If you have a standard white LED grow light, use a conversion factor of 0.015. In the case of 3400 lumens that would be 34000*0.015 = 510µmol. There's an extra "0" in there because of how the lux meter shows the value - they drop a 0 to save space in the display.

Based on the above numbers from the phone, you're getting about 510µmol from that light. Photone is reading about 18% high. That's close to the 16% high that Photone was reading when I tested it (Growcraft flower spectrum + iPhone XSMax) and the error was consistent over all dimmer settings, as expected.

The conversion factor, 0.015, is for a standard white LED. A veg light has more blue light in it so the conversion factor is different. Likewise, a flower light, like the Growcraft or the HLG flower lights, have more red. Unless you're using one of those lights, stick with 0.015.

Or, since you've been able to calibrate Photone using the Uni-T, you keep using Photone but understanding that it's probably reading high so take the reading off of Photone and reduce what it's telling. Based on what you've posted, knock off 16% or, to make it easier, knock off 20%. That will get you in the ballpark.

"ballpark" - that's a big thing to understand. A light meter will allow a grower to set a light level that he wants the plants to have but the important thing is what the plants want so the trick is to turn up the PPFD until you're in the "high light zone", and see how the plants react.

What is the high light zone? That's my just-made-up phrase for the "light saturation point" which is 800-1000µmol for cannabis, in ambient CO2 and assuming that the other factors of the grow are optimized.

With that in mind, aim for 800µmol as a target. I start with 200µmol as seedlings, hit 400 by day 21, when I top the plants, and then ramp up as quickly as I can to the light saturation point.

If the light levels are too high, you will see "photo avoidance" - the leaves nearest the light will taco/canoe or may rotate around their petiole. If you don't watch for that and take action, the leaves will eventually be damaged. It's rare to damage your plants with too much light. Over the course of a grow, I'll probably turn it up a bit to high during early veg.

Each plant is different so, when I'm pushing light levels as high as I can, I completely expect that I'll overshoot. Not a problem - if I see that they're getting too much light, I'll drop the dimmer a bit/use my meter to drop the PPFD, and it takes 30-60 minutes for them to return to their normal shape.

Thanks for that - I agree with everything tech m/hardware wise. Might be about light here but say there are 3 different types of Co2 sensors. The one I trust to actually control my Co2 cylinders just has three input sensors - because it the one that ensures the 100kg cylinders of gas don’t kill anyone.

Same with light sensors and cameras trying to double up as light sensors. The software is capable but to help optimise the offset “algo” or whatever calibration is probably gold for you software side guys?

Anyway - ha! On PPFD levels I run massively higher than you probably you’re growing better than me. I’m very new. But I do pair with target 1000ppm Co2 - high EC and hit temps. I just burned - properly burned my first few leaves. I’m still figuring out its because ai’m running my EC way lower at just 2.4 or my touchy feely is ai’m using a new 1000w LED which as a UV dimmer I’m running at max at 4”

I’m currently figuring that out - so sort of I’m way more extreme on the light levels but until this grow never burned a plant - even ran a 1000w HPS in a 4x4 recently at 8” - but gas and cold air did the trick!

Until the AC broke and the relay on the timer and I was 1500 miles away Hermied but great weed with seeds!

 

[Delps8]

Thanks for that - I agree with everything tech m/hardware wise. Might be about light here but say there are 3 different types of Co2 sensors. The one I trust to actually control my Co2 cylinders just has three input sensors - because it the one that ensures the 100kg cylinders of gas don’t kill anyone.

Agree. We don't like things going "boom" in our grow tent (says the former artillery officer).

Same with light sensors and cameras trying to double up as light sensors. The software is capable but to help optimise the offset “algo” or whatever calibration is probably gold for you software side guys?

Gotta calibrate it. I use an Apogee and had it calibrated. I reads the same as it did before I sent it in - it as inaccurate as the Uni-T (5%±). (The Apogee is more accurate because it's reading PAR but the $32 Uni-T is a much, much better value.)

Anyway - ha! On PPFD levels I run massively higher than you probably you’re growing better than me. I’m very new. But I do pair with target 1000ppm Co2 - high EC and hit temps. I just burned - properly burned my first few leaves. I’m still figuring out its because ai’m running my EC way lower at just 2.4 or my touchy feely is ai’m using a new 1000w LED which as a UV dimmer I’m running at max at 4”

I’m currently figuring that out - so sort of I’m way more extreme on the light levels but until this grow never burned a plant - even ran a 1000w HPS in a 4x4 recently at 8” - but gas and cold air did the trick!

Until the AC broke and the relay on the timer and I was 1500 miles away Hermied but great weed with seeds!

Sounds like you're having a lot of fun with that grow. Lots of learning going on!

 

[NickHardy]

Agree. We don't like things going "boom" in our grow tent (says the former artillery officer).


Gotta calibrate it. I use an Apogee and had it calibrated. I reads the same as it did before I sent it in - it as inaccurate as the Uni-T (5%±). (The Apogee is more accurate because it's reading PAR but the $32 Uni-T is a much, much better value.)


Sounds like you're having a lot of fun with that grow. Lots of learning going on!

Thanks - there’s been a few mad things I’ve done (to say classic held opinion) but ai’ve always at least had a theory. The HPS in a 4x4 (there was a 315CMH with it for some of the grow!) that was being dared to me by like two guys, good mates been growing illicit commercial for 40 years between them. I learned a ton. Had loads of fun too! My current 5x5 is more serious - but still edgy.

Last thing on sensors and going back to Ph which was part of the discussion at the start. Like @Greenvein I think I use a BlueLab ph pen. All it does

You had one job!

Ph and Co2 all I really need.

But light a sensor is a whole lot cheaper than a new set of eyes!

 

[Azimuth]

But light a sensor is a whole lot cheaper than a new set of eyes!

Because you don't have to feed it?

 

[NickHardy]

Because you don't have to feed it?

After detailed analysis of feedback from the Medical Practitioners of the first influx of the Skin&Eyes™ programs revealed that people were looking into the lights to measure them causing damage. Because they were thick. What the organisation claimed were,”Spurious allegations” filed by graduates of the course were later settled out of court.

No joke though - you grow under electric light take care. The sun you won’t accidentally get a full eyeball full of light but in enclosed spaces very easy.

 

[Greenvein]

With that in mind, aim for 800µmol as a target. I start with 200µmol as seedlings, hit 400 by day 21, when I top the plants, and then ramp up as quickly as I can to the light saturation point.

This is pretty much bang on to how I have been growing through observation not far off and everything was measured with this app though a android phone

Cheers for all of that

Until the AC broke and the relay on the timer and I was 1500 miles away Hermied but great weed with seeds!

That runtz that hermied last round only close friends and family get a bit but a friend of a friend wants in! I told him nope it's mine if my buddy shares his that's nothing to do with me very surprised but chuffed at the same time lol

 

[Greenvein]

Last thing on sensors and going back to Ph which was part of the discussion at the start. Like @Greenvein I think I use a BlueLab ph pen. All it does

I'm all Blue lab.. I have a pump in Res pushing mix around and another for my chiller... I noticed if I stir my resovoir when I'm checking pH it drops a few.. but if I just stick my pen in it then I get 5.8 all day piece of S.