logic behind photoacclimation?

Kassiopeija said:

until it hits the top leaf canopy, the rest of the plant gets only a tiny chunk of the energy. If the lighted out plants are only lettuce - it won't matter, but 1.50m tall cannabis plants? This circumstance seems to be neglected/omitted by DLI and I have the feeling this is something Jon may have thought about....?

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kinda saying DLI ppfd whatever... thos are horitoaltal measurments... pick a point in a plane and measure it.. canopy level... im not sure biomass horizontally speaking makes a difference here... theoretically if u had a single leaf covering the entire canopy they would still reccomend starting at 400ppfd or whatever and slowly increasing... so if ur saying its a biomass thing.. ud have to be talking about verticle growth or verticle use of energy...

net photosynthesis is like.... DLI x biomass x limiting factor...... so biomass is already factorered in to net photosythis... it seems more likly the material within the biomass... the leaves... can only handle low ppfd when its young... and higher ppfd levels when its older... or the efficiency that it converts energy is reduced when its young....

so it could be a biomass thing... but i think its more likly that its the biomass cant handel that amount of light efficiently...

DLI is used to measure how much light is being received by plants, often in a greenhouse setting.

For any crop, we already have outdoor farmers that have grown it for generations and can tell you exactly how to grow it in their environment.

Some studies (see Purdue) even have maps showing the outdoor DLI by month for the entire country.

The purpose of DLI is to try and recreate the best possible conditions they can in commercial settings. Most greenhouses by design can only let a certain amount of light in. They use DLI and figure if they need additional lighting...or shade, based upon the location, time of year and crop requirements.

They have devices that measure actual DLI. I dont think the plant mass is material to this, it is a measurement of actual accumulation of umols at a point.

Again from all I have read and know it is not useful to an indoor grower. We can overlight our plants easily, and changes are a mere twist of some dimmers.

Because expert growers (not me) can read their plants and know if they are recieving too much or little light, I believe its of limited use to them, and the guides they provide i.e, XX umols, or XX lux for YY hours , is how we measure it as amateurs...i.e. 800umol for 12 hours.

Imagine having a commercial greenhouse and wanting to insure you have enough light. The charts, a measurement tool, and supplemental lighting could take a grow that would not be viable i.e., not enough DLI available from the sun...and supplement it just right. There is a huge financial calculation there, critically important. Its, I believe...what is NEEDED just to have a solid grow, vs what you seek, which is how to customize the lighting to be *best*.

For that I would focus on spectrum, and the ability to modify it such as California Lightworks controllers. You control spectrum, sunrise and sunset, and how long and intense the lighting, thats a lot to manipulate.

Personally before I went there I would ask others if it is truly beneficial. I have a feeling 99% of pros would say just keep doing runs and you will find answers to most of what you seek over time and through your own experiments.

ComfortCreator said:

DLI is used to measure how much light is being received by plants, often in a greenhouse setting.

For any crop, we already have outdoor farmers that have grown it for generations and can tell you exactly how to grow it in their environment.

Some studies (see Purdue) even have maps showing the outdoor DLI by month for the entire country.

The purpose of DLI is to try and recreate the best possible conditions they can in commercial settings. Most greenhouses by design can only let a certain amount of light in. They use DLI and figure if they need additional lighting...or shade, based upon the location, time of year and crop requirements.

They have devices that measure actual DLI. I dont think the plant mass is material to this, it is a measurement of actual accumulation of umols at a point.

Again from all I have read and know it is not useful to an indoor grower. We can overlight our plants easily, and changes are a mere twist of some dimmers.

Because expert growers (not me) can read their plants and know if they are recieving too much or little light, I believe its of limited use to them, and the guides they provide i.e, XX umols, or XX lux for YY hours , is how we measure it as amateurs...i.e. 800umol for 12 hours.

Imagine having a commercial greenhouse and wanting to insure you have enough light. The charts, a measurement tool, and supplemental lighting could take a grow that would not be viable i.e., not enough DLI available from the sun...and supplement it just right. There is a huge financial calculation there, critically important. Its, I believe...what is NEEDED just to have a solid grow, vs what you seek, which is how to customize the lighting to be *best*.

For that I would focus on spectrum, and the ability to modify it such as California Lightworks controllers. You control spectrum, sunrise and sunset, and how long and intense the lighting, thats a lot to manipulate.

Personally before I went there I would ask others if it is truly beneficial. I have a feeling 99% of pros would say just keep doing runs and you will find answers to most of what you seek over time and through your own experiments.

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i understand how to calculate DLI.... and the whole concept.... i use the appogee extended range sensor w the micro cashe.... DLI is huge w indoor growing specifically LEDs... and its because of the limiting factor thing.... for instance... if ur looking for a specific DLI its really all about ppfd... so you want the plant to get lets say 1000ppfd at canopy... thats easy you can do that HPS... but if ur adding co2 you want leaf temp 80+... leaf temp basically being the limiting factor on co2 obsortion... you need to work w your LED setup to begetting 1000ppfd at canopy and 80 f leaf temp... if you were going to change leaf temp w HPS by moving it up and down you would also chnage ur ppfd..... w LEDs you chnage the wattage at the driver and try and use the combo of the height and power to maintain 1000ppfd and 80+ leaf temp...

im confused about the science behind photoacclimation...

for instnce w the outdoor greenhouse plants were under very high light in june and july DLIs in the 60s... but they spent the last month slowly ticking down to like 35 on september 1... so i go these new LEDs inside i figure im going to put the HPSs in the grenhouse... can i push the plants back up to a DLI of 60 right away? they have recieved DLIs in the 60s in the past... but it was a month ago... have they been photo acclimated back down lol... idk...

a big question that would help is.. lets say if ur following those charts... and you want to push the DLIs higher...

are the extra photons wasted because the plant cant turn them into energy...
or
do the extra photons actually harm the plant...

ComfortCreator said:

He would tell you every 3 to 4 weeks they can handle another 5DLI or so. There is a recommended maximum it reaches while still growing flowers. Then it can be increased a bit more for ripening before trailing off for the finish.

Is DLI identical for every strain? No...so the curve is what then exactly? A guide. There is no magic in those numbers its a pretty smooth graph.

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you do you think the dip in DLI at week 11 or what looks like week 5 of flower... he pushes them u up to 35 in week 10... drops back to 32 in week 11.. then back to 35 then to 40...

the only reason i think this could be some kind of thc maximising flower scheudle or something is cuz the final dip woiuld make sence if ur looking for THC and not CBD.... im not sure this is the case... i look at this chart and i see thc decreasing and cdb increasing around the time he start to dial back his DLI....

JonCreighton said:

you do you think the dip in DLI at week 11 or what looks like week 5 of flower... he pushes them u up to 35 in week 10... drops back to 32 in week 11.. then back to 35 then to 40...

the only reason i think this could be some kind of thc maximising flower scheudle or something is cuz the final dip woiuld make sence if ur looking for THC and not CBD.... im not sure this is the case... i look at this chart and i see thc decreasing and cdb increasing around the time he start to dial back his DLI....

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Why is that chart the gospel? You reference each detail as if it is carefully calibrated.

The outdoors may get 60 DLI, but.the greenhouses using the DLI measurement are not squeezing out 60DLI from that. The paper I referenced before even discussed in detail they often dont have the minimum needed, let alone the maximum possible.

I can overlight my grow space no problem, any time in the cycle. I dont understand why you infer so much from the chart....?

ComfortCreator said:

Why is that chart the gospel? You reference each detail as if it is carefully calibrated.

The outdoors may get 60 DLI, but.the greenhouses using the DLI measurement are not squeezing out 60DLI from that. The paper I referenced before even discussed in detail they often dont have the minimum needed, let alone the maximum possible.

I can overlight my grow space no problem, any time in the cycle. I dont understand why you infer so much from the chart....?

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im not saying this is gospel... im trying to use decudtive reason to figure out his logic... this is a professional cannabis cultivator... hes knows what hes doing and why hes doing it.... so id like to know also...

and the interesting thing about the graph i keep talking about is all the other ones seem to be yield oriented.... they slowly rise over the course of flower... but higginbothams doesnt... if ur looking for yield... why would you lower your light for an entire week in mid flower just to raise theem again a week later... this would seem to sacrifice yield.... so they question is why is he sacrificing yield... is this a quality oriented flower schedule??

my hypothosis is...

there are specific times durring the flower cycle where the plant is focused on cannabinoid prodcution.... hes highlighting thse times as opposed to the times where the plant is generating plant mass...

(Theory)

What if all it is, is simply data? Simply a trend, to match with all your other data. To keep an accurate record from grow, to grow. A record and that's all. That simple.

So, you have hundreds / thousands of plants and something goes wrong all of a sudden. You want to be so sure, what you believe is wrong, is the right guess. (big money)
You then go ahead and match current data. (not just DLI) To all other previous and existing data. To look for any trends, discrepancies, changes or whatever it may be.
It could save one hell of a lot of money...

Honestly i think it's just an excuse to utilize products that can be dimmed.

I don't think its necessary to change the DLI at all during flower... If you're doing anything over 40 your results should be great.

I actually think it's much better if the DLI is fixed and constant (together with automated watering)... So the plant can get used to the conditions and grow in a very controlled environment.

eyderbuddy said:

Honestly i think it's just an excuse to utilize products that can be dimmed.

I don't think its necessary to change the DLI at all during flower... If you're doing anything over 40 your results should be great.

I actually think it's much better if the DLI is fixed and constant (together with automated watering)... So the plant can get used to the conditions and grow in a very controlled environment.

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how do u do ur move to flower if u don't mind saying

Aussieaceae said:

(Theory)

What if all it is, is simply data? Simply a trend, to match with all your other data. To keep an accurate record from grow, to grow. A record and that's all. That simple.

So, you have hundreds / thousands of plants and something goes wrong all of a sudden. You want to be so sure, what you believe is wrong, is the right guess. (big money)
You then go ahead and match current data. (not just DLI) To all other previous and existing data. To look for any trends, discrepancies, changes or whatever it may be.
It could save one hell of a lot of money...

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could be... if i could push back a little id say

this is generally my favorite resource tho... keep in mind he sells light sensors... so.. u kno...

seems like u start w the lighting....

watch