Ppfd :-)

[Kassiopeija]

The internal workings of a leaf do not work on conductive and convective heat from air, this is merely part of the leaf budget and you and others with leds need to stop bending science with sheer will.

But I'm not an "LED guy" . I only have 1 big LED rack and 5 small lamps for a total of 400W. But HID lamps that draw 1750W. And even a greater multitude of old CFLs which I sometimes also put to use on clones/seedlings... I still use that "soft light" at point blank range or to light out the corners, or below the leaf canopy on big plants.

And that LED is actually the latest investment because this summer has been the second brutal hot summer in row, running lights during the night I had over 36°C in my big tent under 600 W HPS but not over 30°C with Cree 3590 300W in a tent at the same room, with the LED tent being only 1/3 of the volume of the HPS tent! I just try to keep an open mind not only with lights... for example fertilizers, soil additives & stimulants: 40 different bottles not even counting the stuff I pull directly from nature.... with lots of new interesting stuff on my list that I also need like Chitosan

and since I came to this forum (to learn) I tried to make sense of the things you write but I really have a hard time following you. It may be a language issue on my part....

Thank you! Great info you shared.
I agree about lower temps being beneficial under led. I like 76-82• / 60-65%. I do not feel that raising ambient temps is the key to raising leaf temps. You are not discussing leaf temps or its incorporated in the reading? Im no scholar! Lol!
I am well aware of this last one where green is just as useful as red + blue.
The led company i use taught me this stuff when i first bought one. Thats when burple was fading out & i was buying the closest to the sun i could get at the time, called the "Equetorial Spectrum" .
My theory is not that green or any specific nm's are useless, each play their role.
I'm suggesting that simply because it is artificial light , that there is an over abundance in full wavelengths of 400-700nm. White leds. I feel the plant would bennifit from reducing any overabundances as well as adding some nm's outside the McCree curve to touch the plant everywhere we can. Some do great though. Its just not simple overnight learning.

Yes, all references made is ambient temperature. Most scenarios described are either outdoors or from a controlled experiment.
Yes, direct leaf temp would probably be a better place to look at and draw some insights from, but I would need to get myself another instrument to measure this. And get some experience with the numbers in order to be able to put things into relation... maybe Santa Claus has it in store for me already?

Landplants had about 500 million years to adapt to natural light. From a certain standpoint it would make sense to mimick the natural spectrum as close as possible because there may be -or not- still some unfound variables in how plants react to that broad natural spectrum.

I had a one-time experience few years ago when living in the hills with some strains from Nirvana:
raised in May indoors with very soft CFL light only, I put them outdoors directly under the strong June sun (albeit at a spot where they got direct sun only for 5-6h a day.) Plants at that stage were already 50cm high. Under the first really sunny no cloudy day all plants' leaves showed totally irregular bleached white spots on all leaves (I've never seen such an equal damage outlook on any picture here or in another forum) with all plants loosing all their damaged leaves. (they bleached even more, wrinkled and fell off on their own). After that, they grew new leaves which were absolutely able to withstand an even harsher sun at a higher altitude (+150m) for twice the duration with the sun even moving more into the zenith.

My bet is that the first encounter with UVC radiation destroyed those leaves, and that the plants reacted with the buildup of secondairy metabolites to counter that. However, IDK. It could've been UVA or UVB or maybe it was just too much visible light or even a combination of all these reasons.... but growers actually already use light in some of these spectra with no resemblance of said unique damage.

If we would mimick the sun UVC would also be necessary to some extend. I'm aware that this kind of radiation actually creates cellular/DNA damage - but wouldn't that also be useful in order to counter botrytis/PM? Small pests are much faster destroyed by UVC as big lifeforms that potentially have the power to repair themselves. UVC is a powerful sterilization tool. Maybe someone already did experiment with that?

 

[Kingrow1]

Your thermometer is reading light radiation more than air temps. Tents are not microclimates but linked directly to air temperature of air they pull in.

Its not the lights making it hot either if you have only hot air to pull in.

Your figures suggeat you have some to go before you discuss led hype and slanser hps as hot.

A heater will heat air more efficiently yet you cite a 600w bulb as a more efficient heater of air than a 600watt heater from shops.... Science is so loose with leds and that creates those who fail to question the hype properly

But I'm not an "LED guy" . I only have 1 big LED rack and 5 small lamps for a total of 400W. But HID lamps that draw 1750W. And even a greater multitude of old CFLs which I sometimes also put to use on clones/seedlings... I still use that "soft light" at point blank range or to light out the corners, or below the leaf canopy on big plants.

And that LED is actually the latest investment because this summer has been the second brutal hot summer in row, running lights during the night I had over 36°C in my big tent under 600 W HPS but not over 30°C with Cree 3590 300W in a tent at the same room, with the LED tent being only 1/3 of the volume of the HPS tent! I just try to keep an open mind not only with lights... for example fertilizers, soil additives & stimulants: 40 different bottles not even counting the stuff I pull directly from nature.... with lots of new interesting stuff on my list that I also need like Chitosan

and since I came to this forum (to learn) I tried to make sense of the things you write but I really have a hard time following you. It may be a language issue on my part....


Yes, all references made is ambient temperature. Most scenarios described are either outdoors or from a controlled experiment.
Yes, direct leaf temp would probably be a better place to look at and draw some insights from, but I would need to get myself another instrument to measure this. And get some experience with the numbers in order to be able to put things into relation... maybe Santa Claus has it in store for me already?

Landplants had about 500 million years to adapt to natural light. From a certain standpoint it would make sense to mimick the natural spectrum as close as possible because there may be -or not- still some unfound variables in how plants react to that broad natural spectrum.

I had a one-time experience few years ago when living in the hills with some strains from Nirvana:
raised in May indoors with very soft CFL light only, I put them outdoors directly under the strong June sun (albeit at a spot where they got direct sun only for 5-6h a day.) Plants at that stage were already 50cm high. Under the first really sunny no cloudy day all plants' leaves showed totally irregular bleached white spots on all leaves (I've never seen such an equal damage outlook on any picture here or in another forum) with all plants loosing all their damaged leaves. (they bleached even more, wrinkled and fell off on their own). After that, they grew new leaves which were absolutely able to withstand an even harsher sun at a higher altitude (+150m) for twice the duration with the sun even moving more into the zenith.

My bet is that the first encounter with UVC radiation destroyed those leaves, and that the plants reacted with the buildup of secondairy metabolites to counter that. However, IDK. It could've been UVA or UVB or maybe it was just too much visible light, but growers actually already use light in these spectra with no resemblance of said unique damage.

If we would mimick the sun UVC would also be necessary to some extend. I'm aware that this kind of radiation actually creates cellular/DNA damage - but wouldn't that also be useful in order to counter botrytis/PM? Small pests are much faster destroyed by big lifeforms that potentially have the power to repair themselves. UVC is a powerful sterilization tool. Maybe someone already did experiment with that?

 

[Kassiopeija]

Your thermometer is reading light radiation more than air temps. Tents are not microclimates but linked directly to air temperature of air they pull in.

Its not the lights making it hot either if you have only hot air to pull in.

Your figures suggeat you have some to go before you discuss led hype and slanser hps as hot.

A heater will heat air more efficiently yet you cite a 600w bulb as a more efficient heater of air than a 600watt heater from shops.... Science is so loose with leds and that creates those who fail to question the hype properly

I have combined rH/thermometers at
- the fresh air intake
- air outtake (beginning & end)
- inside the pot
- right onto the pot
- directly on the canopy
- at the top of the tent some distance away from the spreader
- outside the tent in the growroom

some of the meters are actually manually boxed in order to shield them from the lamps radiation. 4 different brands (because I can "normalize" them against each other). And lots more on my cureing boxes. This is really important to me... haven't you been the guy questioning the importancy of rH in another thread....? Yes I remember that

Because there was an eternal debate on grower.ch where best to put them so I simply put them everywhere I found them useful and during one grow, made a list and collected their data every few days. Just so I have data to compare on the temperature/rH development.
Actually I would like have a digital program to collect said data and a program that displays that data in various graphs, but this is on my list. Donno if such program actually already exists.

edit:
what's so hard to believe with those temps? this summer was hot, and if normal room temps are already around ~28°C a 600W energy release has no trouble to up that by a few C. Especially if said lamp does not only emit visible light but also heat radiation. The passive cooling on the Cree's also got considerably hot (had to install an active fan bc this will increase the lifespan of the chips) but this heat didn't radiate as strongly as the stuff which was emitted from the 600W HPS/MH.

The only thing I didn't measure was leaf temps but that could be taken care of in the future

 

[Kingrow1]

The fact you have some meters in the wrong places shows your confusion on basic subjects.

Just put meter outside tent, thats the most important reading for you as you learn

I have combined rH/thermometers at
- the fresh air intake
- air outtake (beginning & end)
- inside the pot
- right onto the pot
- directly on the canopy
- at the top of the tent some distance away from the spreader
- outside the tent in the growroom

some of the meters are actually manually boxed in order to shield them from the lamps radiation. 4 different brands (because I can "normalize" them against each other). And lots more on my cureing boxes. This is really important to me... haven't you been the guy questioning the importancy of rH in another thread....? Yes I remember that

Because there was an eternal debate on grower.ch where best to put them so I simply put them everywhere I found them useful and during one grow, made a list and collected their data every few days. Just so I have data to compare on the temperature/rH development.
Actually I would like have a digital program to collect said data and a program that displays that data in various graphs, but this is on my list. Donno if such program actually already exists.

 

[Kassiopeija]

A heater will heat air more efficiently yet you cite a 600w bulb as a more efficient heater of air than a 600watt heater from shops....

No I didn't state that at all.
I'm simply the opinion that if temps are too cold for LED (below 25°C) its better to use a HID instead of LED. I've seen some "cold grows" from LED and the buds don't get heavy. Because the plants metabolism now caps. And if that would still be too cold I'd try isolate the pots and use cooling matts but not use a heater to heat up the ambient air because most of said air is pulled outta the growroom by the exhaust fan anyway... or add another HID light because light is a big factor on harvest weight. And I usually grow big plants (which call usually for lollipopping but I could -in theory- install sidelighting but actually, personally I have no probs with low temps in winter, but high temps in summer...)

 

[Kassiopeija]

The fact you have some meters in the wrong places shows your confusion on basic subjects.

Just put meter outside tent, thats the most important reading for you as you learn

this is just for me to collect data. what I then make ot of that data is an entire different topic. and yeah, since I started to grow organically I really need to know temps of the soillife.

But I just realize that if you're of the opinion the only thermo necessary is outside the tent you for sure don't witness how hot a HPS can get

 

[hybridway2]

But I'm not an "LED guy" . I only have 1 big LED rack and 5 small lamps for a total of 400W. But HID lamps that draw 1750W. And even a greater multitude of old CFLs which I sometimes also put to use on clones/seedlings... I still use that "soft light" at point blank range or to light out the corners, or below the leaf canopy on big plants.

And that LED is actually the latest investment because this summer has been the second brutal hot summer in row, running lights during the night I had over 36°C in my big tent under 600 W HPS but not over 30°C with Cree 3590 300W in a tent at the same room, with the LED tent being only 1/3 of the volume of the HPS tent! I just try to keep an open mind not only with lights... for example fertilizers, soil additives & stimulants: 40 different bottles not even counting the stuff I pull directly from nature.... with lots of new interesting stuff on my list that I also need like Chitosan

and since I came to this forum (to learn) I tried to make sense of the things you write but I really have a hard time following you. It may be a language issue on my part....


Yes, all references made is ambient temperature. Most scenarios described are either outdoors or from a controlled experiment.
Yes, direct leaf temp would probably be a better place to look at and draw some insights from, but I would need to get myself another instrument to measure this. And get some experience with the numbers in order to be able to put things into relation... maybe Santa Claus has it in store for me already?

Landplants had about 500 million years to adapt to natural light. From a certain standpoint it would make sense to mimick the natural spectrum as close as possible because there may be -or not- still some unfound variables in how plants react to that broad natural spectrum.

I had a one-time experience few years ago when living in the hills with some strains from Nirvana:
raised in May indoors with very soft CFL light only, I put them outdoors directly under the strong June sun (albeit at a spot where they got direct sun only for 5-6h a day.) Plants at that stage were already 50cm high. Under the first really sunny no cloudy day all plants' leaves showed totally irregular bleached white spots on all leaves (I've never seen such an equal damage outlook on any picture here or in another forum) with all plants loosing all their damaged leaves. (they bleached even more, wrinkled and fell off on their own). After that, they grew new leaves which were absolutely able to withstand an even harsher sun at a higher altitude (+150m) for twice the duration with the sun even moving more into the zenith.

My bet is that the first encounter with UVC radiation destroyed those leaves, and that the plants reacted with the buildup of secondairy metabolites to counter that. However, IDK. It could've been UVA or UVB or maybe it was just too much visible light or even a combination of all these reasons.... but growers actually already use light in some of these spectra with no resemblance of said unique damage.

If we would mimick the sun UVC would also be necessary to some extend. I'm aware that this kind of radiation actually creates cellular/DNA damage - but wouldn't that also be useful in order to counter botrytis/PM? Small pests are much faster destroyed by UVC as big lifeforms that potentially have the power to repair themselves. UVC is a powerful sterilization tool. Maybe someone already did experiment with that?

From what i gathered using my ir gun was average -2• Ambient on led leaves. +5-8• under vented hps (regular room fans on) That is why led users are chasing ambient temps hoping this does the trick for the leaves.
But like the sun, when an HPS light touches you, you feel the warmth from afar. Increasing leaf temp. Over ambient.
One reason some led companies running cased fixtures adapted active heatsink fans facing down toward the plants.
I think thats a starting point to understanding something.

 

[hybridway2]

I have combined rH/thermometers at
- the fresh air intake
- air outtake (beginning & end)
- inside the pot
- right onto the pot
- directly on the canopy
- at the top of the tent some distance away from the spreader
- outside the tent in the growroom

some of the meters are actually manually boxed in order to shield them from the lamps radiation. 4 different brands (because I can "normalize" them against each other). And lots more on my cureing boxes. This is really important to me... haven't you been the guy questioning the importancy of rH in another thread....? Yes I remember that

Because there was an eternal debate on grower.ch where best to put them so I simply put them everywhere I found them useful and during one grow, made a list and collected their data every few days. Just so I have data to compare on the temperature/rH development.
Actually I would like have a digital program to collect said data and a program that displays that data in various graphs, but this is on my list. Donno if such program actually already exists.

edit:
what's so hard to believe with those temps? this summer was hot, and if normal room temps are already around ~28°C a 600W energy release has no trouble to up that by a few C. Especially if said lamp does not only emit visible light but also heat radiation. The passive cooling on the Cree's also got considerably hot (had to install an active fan bc this will increase the lifespan of the chips) but this heat didn't radiate as strongly as the stuff which was emitted from the 600W HPS/MH.

The only thing I didn't measure was leaf temps but that could be taken care of in the future

@Renfro may be able to point you in the right direction for humidity monitoring?
He got some nice tech recently.

 

[Renfro]

but this heat didn't radiate as strongly as the stuff which was emitted from the 600W HPS/MH.

The HPS has infrared emission, the LED does not.

 

[Kushash]

But I'm not an "LED guy" . I only have 1 big LED rack and 5 small lamps for a total of 400W. But HID lamps that draw 1750W. And even a greater multitude of old CFLs which I sometimes also put to use on clones/seedlings... I still use that "soft light" at point blank range or to light out the corners, or below the leaf canopy on big plants.

And that LED is actually the latest investment because this summer has been the second brutal hot summer in row, running lights during the night I had over 36°C in my big tent under 600 W HPS but not over 30°C with Cree 3590 300W in a tent at the same room, with the LED tent being only 1/3 of the volume of the HPS tent! I just try to keep an open mind not only with lights... for example fertilizers, soil additives & stimulants: 40 different bottles not even counting the stuff I pull directly from nature.... with lots of new interesting stuff on my list that I also need like Chitosan

and since I came to this forum (to learn) I tried to make sense of the things you write but I really have a hard time following you. It may be a language issue on my part....


Yes, all references made is ambient temperature. Most scenarios described are either outdoors or from a controlled experiment.
Yes, direct leaf temp would probably be a better place to look at and draw some insights from, but I would need to get myself another instrument to measure this. And get some experience with the numbers in order to be able to put things into relation... maybe Santa Claus has it in store for me already?

Landplants had about 500 million years to adapt to natural light. From a certain standpoint it would make sense to mimick the natural spectrum as close as possible because there may be -or not- still some unfound variables in how plants react to that broad natural spectrum.

I had a one-time experience few years ago when living in the hills with some strains from Nirvana:
raised in May indoors with very soft CFL light only, I put them outdoors directly under the strong June sun (albeit at a spot where they got direct sun only for 5-6h a day.) Plants at that stage were already 50cm high. Under the first really sunny no cloudy day all plants' leaves showed totally irregular bleached white spots on all leaves (I've never seen such an equal damage outlook on any picture here or in another forum) with all plants loosing all their damaged leaves. (they bleached even more, wrinkled and fell off on their own). After that, they grew new leaves which were absolutely able to withstand an even harsher sun at a higher altitude (+150m) for twice the duration with the sun even moving more into the zenith.

My bet is that the first encounter with UVC radiation destroyed those leaves, and that the plants reacted with the buildup of secondairy metabolites to counter that. However, IDK. It could've been UVA or UVB or maybe it was just too much visible light or even a combination of all these reasons.... but growers actually already use light in some of these spectra with no resemblance of said unique damage.

If we would mimick the sun UVC would also be necessary to some extend. I'm aware that this kind of radiation actually creates cellular/DNA damage - but wouldn't that also be useful in order to counter botrytis/PM? Small pests are much faster destroyed by UVC as big lifeforms that potentially have the power to repair themselves. UVC is a powerful sterilization tool. Maybe someone already did experiment with that?

Thought you might enjoy this link if you haven't read it.

The future of agriculture is computerized

Researchers at the MIT Media Lab Open Agriculture Initiative have used computer algorithms to determine the optimal growing conditions to improve basil plants’ taste by maximizing the concentration of flavorful molecules known as volatile compounds.

news.mit.edu

@hybridway2 any idea what kind of LED lighting is being used in the pic they show in the link above?

 

[Kushash]

Seriously!

Any LED guys able to look at this light and tell what's being used?

Can't tell. Is it blurple, white, and far red or something from NASA?

Might be the light @OneHitDone is looking for.

 

[CanadianJim]

Seriously!

Any LED guys able to look at this light and tell what's being used?

Can't tell. Is it blurple, white, and far red or something from NASA?

Might be the light @OneHitDone is looking for.


View attachment 4439006

I can't tell what it is, but it looks a lot like the ones those researchers in Toronto are using to study how light spectra influence the uptake of nutrients in food crops. They're hoping to repurpose warehouses to grow crops indoors, especially in cold or otherwise unsuitable environments, or in cities. The study of the uptake of nutrients is to try to make sure indoor crops are as nutritious as outdoor. They have shown, so far, that crops like lettuce and spinach have different levels of, for example, magnesium depending on what light they're exposed to. You should be able to find references through google. Iirc they're connected to the University of Toronto.

 

[OneHitDone]

Seriously!

Any LED guys able to look at this light and tell what's being used?

Can't tell. Is it blurple, white, and far red or something from NASA?

Might be the light @OneHitDone is looking for.


View attachment 4439006

Appears to be Red, White, and Blue? Until I see an led that is offering a "broader" spectrum and reaching way deeper into the far reds I'm good

 

[hybridway2]

Appears to be Red, White, and Blue? Until I see an led that is offering a "broader" spectrum and reaching way deeper into the far reds I'm good

Any deeper into far reds then 740 n you wont be seeing it at all. Lol! But i get it, just not sure how that would be doable w/o adding CHPS bulbs.

 

[OneHitDone]

Any deeper into far reds then 740 n you wont be seeing it at all. Lol! But i get it, just not sure how that would be doable w/o adding CHPS bulbs.
View attachment 4439133

Don't mean a Deep Red dominant spectrum home slice lol

 

[CanadianJim]

Even cheap Chinese blurples are available with IR and UV LEDs.
Yes, IR and UV LEDs do exist, but up until China got involved they were too expensive to be used for anything but military purposes.

Any deeper into far reds then 740 n you wont be seeing it at all. Lol! But i get it, just not sure how that would be doable w/o adding CHPS bulbs.
View attachment 4439133

 

[Kassiopeija]

Thought you might enjoy this link if you haven't read it.

The future of agriculture is computerized

Researchers at the MIT Media Lab Open Agriculture Initiative have used computer algorithms to determine the optimal growing conditions to improve basil plants’ taste by maximizing the concentration of flavorful molecules known as volatile compounds.

news.mit.edu

@hybridway2 any idea what kind of LED lighting is being used in the pic they show in the link above?

Thank you very much it was very informative. AI rocks!

One thing which I find important to point out is that that this article states that plants do better under an unnatural condition, ie. 24/0 lightcycle during veg.
The question in charge is if this is also true for Cannabis? Personally I like to veg under 24h light because I feel the plants grow faster. I also see no reason of why there should be a buildup of generative plant hormones during veg. I've been told that under 18/6 plants are more healthy and with respect to the article linked on photorespiration, there's some entries/processes going on in plants that happen only during the night phase but IDK.

HID lights will also increase their lifespan/efficiency when they're constantly on, and 24/0 delivers also more energy which could in turn mean less ppfd is needed, which, in turn could mean one could light out a greater area with the same lamp.

What pro's & con's are also there?

 

[Kassiopeija]

From what i gathered using my ir gun was average -2• Ambient on led leaves. +5-8• under vented hps (regular room fans on) That is why led users are chasing ambient temps hoping this does the trick for the leaves.
But like the sun, when an HPS light touches you, you feel the warmth from afar. Increasing leaf temp. Over ambient.
One reason some led companies running cased fixtures adapted active heatsink fans facing down toward the plants.
I think thats a starting point to understanding something.

Your temperature differences are actually very close to my "amateur" measurements. And yeah, I did blow most of the heat of the 4 75W COBs down at the canopy, just because I thought it may save some electricity this way if one oscillating fan does two jobs at the same time.

 

[Kassiopeija]

Any deeper into far reds then 740 n you wont be seeing it at all. Lol! But i get it, just not sure how that would be doable w/o adding CHPS bulbs.
View attachment 4439133

How efficient are these CHPS in terms of phyto-luminosity in comparison to ordinairy reference HPS?

 

[hybridway2]

How efficient are these CHPS in terms of phyto-luminosity in comparison to ordinairy reference HPS?

Not very. Have no #'s but i feel i couldve done better under a normal Hortilux.
Funny, it doesn't even look red when fired up. Doesn't take much green to balance to the human eye i guess. More of a heat lamp then a grow lamp or 1/2 n 1/2.

24 hrs veg is no good IMO. 16 is where I'm at do to the plants looking done for the day then. But normally 18/6.