Ppfd problems.

Apocalyptical

Active Member
Is anyone aware of what happens to a plant that is oversaturated with an excess of ppfd? What kind of effects it has on the plant, in terms of its metabolism?
 

Beehive

Well-Known Member
You get a higher power bill.

Wanna see something fantastic? Measure the ppfd of straight sunlight. Measure the lux.
 

Apocalyptical

Active Member
You get a higher power bill.

Wanna see something fantastic? Measure the ppfd of straight sunlight. Measure the lux.
See, thats what i was thinking myself. The sun is powerful af. But on some sites, im reading that it can fuck with the plants metabolism (i seem to have issues everytime i crank my light all the way up). I always thought that the very first sign that a light was too powerful, would be bleaching of the plant. I dont know. Ive ruled out vpd for the same reason (outdoor can be screwy/many people showing great success while heavily outside of vpd range). These plants are finicky af lol.
 

LEDTonic - Max

Active Member
Photosynthesis can become light-saturated and plants can dissipate excess photons as heat, rather than use them for photosynthesis.
Where the saturation point is reached depends on many different factors. It differs between plant species, between strains within the same species and to some degree, probably even between individuals within the same strain.

Sunlight is strong, upwards 1500-2000 PPFD in sunny places, but very few plants (if any?) prefer 1500-2000 PPFD over 1000 PPFD (at ambient CO2).
Also, the sun's intensity changes throughout the day. Illuminating our plants with 1600 PPFD indoors for a whole day is a lot different than if they are experiencing 1600 PPFD outdoors for a couple of hours in the middle of the day. DLI gives a more accurate value and takes varying light intensities into account. The DLI value also changes based on season and depends on where you live.
 

Apocalyptical

Active Member
Photosynthesis can become light-saturated and plants can dissipate excess photons as heat, rather than use them for photosynthesis.
Where the saturation point is reached depends on many different factors. It differs between plant species, between strains within the same species and to some degree, probably even between individuals within the same strain.

Sunlight is strong, upwards 1500-2000 PPFD in sunny places, but very few plants (if any?) prefer 1500-2000 PPFD over 1000 PPFD (at ambient CO2).
Also, the sun's intensity changes throughout the day. Illuminating our plants with 1600 PPFD indoors for a whole day is a lot different than if they are experiencing 1600 PPFD outdoors for a couple of hours in the middle of the day. DLI gives a more accurate value and takes varying light intensities into account. The DLI value also changes based on season and depends on where you live.
Funnily enough.. im covering the photo systems 680 and 700 in class right now, but noooope. They sure as hell dont tell you how much is too much for cannabis XD :wall::) Lmao. Are you aware of any potential ill-effects, in terms of lets say metabolic processes, or anything of the sorts, that could explain the drooping? Or would it be possible that that is something else. I cant seem to find much material on the matter. That is at least consistent/clear/concise.
 

LEDTonic - Max

Active Member
Funnily enough.. im covering the photo systems 680 and 700 in class right now, but noooope. They sure as hell dont tell you how much is too much for cannabis XD :wall::) Lmao. Are you aware of any potential ill-effects, in terms of lets say metabolic processes, or anything of the sorts, that could explain the drooping? Or would it be possible that that is something else. I cant seem to find much material on the matter. That is at least consistent/clear/concise.
Sweet! I don't know what causes the drooping, unfortunately. We should be able to find some good information by searching for information related to Photoinhibition and/or Photosystem II. You probably already know this, but Researchgate is a great place to search for this type of info. Here is one article I just found which seems interesting, although I've only glanced at it. Found it by googling Photosystem 2 +too much light/photoinhibition. You should find plenty of other articles by doing similar searches ;-)
 
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