Kill 'me or Keep 'em?

[Rootsruler]

100% correct brother… air temps mean nothing and with the cost of an IR temp gun there really is no excuse not to.

Even VPD calculations are incorrect without leaf temps taken into account

Should lights off leaf temps also be taken into account? If so where do we want to be on that for maximum transpiration?

 

[Aqua Man]

Should lights off leaf temps also be taken into account? If so where do we want to be on that for maximum transpiration?

Plants barely transpire during lights out… light drives transpiration. Just made me question something myself…. I wonder how much translocation of nutrients happens between light and dark cycles…. Something i have never looked into

 

[Rootsruler]

Plants barely transpire during lights out… light drives transpiration. Just made me question something myself…. I wonder how much translocation of nutrients happens between light and dark cycles…. Something i have never looked into

So is there anything that can be done at lights out that will improve the overall grow? What metabolic processes are happening at lights out?

 

[Aqua Man]

So is there anything that can be done at lights out that will improve the overall grow?

It all depends on all of the key factors…. Anything is a broad statement…. So yes but it depends on whats going on to begin with. So i cannot give a broad statement that says x,y,z WILL make an improvement under all conditions

 

[Aqua Man]

In cannabis there are probably only a few absolutes and the rest is all it depends

 

[growsinse79]

So is there anything that can be done at lights out that will improve the overall grow? What metabolic processes are happening at lights out?

Leaves and branches replenish their water storage during the night, increasing their weight and causing them to droop down. Terrestrial laser scanning is a remote sensing technique that can produce a 3D representation of the surroundings with millimetre accuracy

Water makes tree branches droop at night

Terrestrial laser scanning data show that trees move their branches in a diurnal pattern, settling down for the night -- as if falling asleep. Changes in the water status of leaves and branches causes branches to move downward at night, up to 20 cm depending on the tree species.

www.sciencedaily.com

 

[Rootsruler]

It all depends on all of the key factors…. Anything is a broad statement…. So yes but it depends on whats going on to begin with. So i cannot give a broad statement that says x,y,z WILL make an improvement under all conditions

OK....some foundation to work off of. Lights on specs are all within range. Leaves are up and happy during the day and vigorous growth is happening. Lights go out and plants go to sleep. Lights out environmental specs all fall within acceptable range. Anything else I can do to make it better? Is that too general a foundation or does there need to be some specific imbalance happening where we need to tweak something else to get it back in balance?

According to RQS...

"In the dark, plants use the energy they produce during the day (or in the presence of light) to turn carbon dioxide from the environment into glucose and other simple sugars that they can use to help further fuel their growth."

 

[Aqua Man]

OK....some foundation to work off of. Lights on specs are all within range. Leaves are up and happy during the day and vigorous growth is happening. Lights go out and plants go to sleep. Lights out environmental specs all fall within acceptable range. Anything else I can do to make it better? Is that too general a foundation or does there need to be some specific imbalance happening where we need to tweak something else to get it back in balance?

According to RQS...

"In the dark, plants use the energy they produce during the day (or in the presence of light) to turn carbon dioxide from the environment into glucose and other simple sugars that they can use to help further fuel their growth."

Ok so yes that’s absolutely accurate but to the ratio of translocation of energy and nutrients in relation to lights on does it remain the same, higher or lower is what i was kinda thinking i need to look into because that answer i dont have… assumption would be the same or higher imo. Not much else can be done to improve growth if environmental factors are inline other than high o2 in the roots and PGRs that i can think of. No not co2 because that impacts the making of energy during lights on and a bit of other processes but lets not go there.


As said above plants droop due to more water in the leaves at night but the reason why there is more water in the leaves is….. because in the absence of light plants reduce the opening of the stomata and in turn transpiration this mean less water movement through the plant and less turgor leaving more water trapped in the plant leaves but they continue respiration and translocation of nutrients and energy.

 

[Rootsruler]

Ok so yes that’s absolutely accurate but to the ratio of translocation of energy and nutrients in relation to lights on does it remain the same, higher or lower is what i was kinda thinking i need to look into because that answer i dont have… assumption would be the same or higher imo. Not much else can be done to improve growth if environmental factors are inline other than high o2 in the roots and PGRs that i can think of. No not co2 because that impacts the making of energy during lights on and a bit of other processes but lets not go there.


As said above plants droop due to more water in the leaves at night but the reason why there is more water in the leaves is….. because in the absence of light plants reduce the opening of the stomata and in turn transpiration this mean less water movement through the plant and less turgor leaving more water trapped in the plant leaves but they continue respiration and translocation of nutrients and energy.

The RQS statement still didn't really answer my question or maybe I'm not reading it right. It says that at night they use the energy they produced during the day to help further fuel growth. Ok...but what growth are they further fueling?

My understanding from that is that as they sleep they grow, maybe at not as high a rate but they grow. Is there something I'm missing from that statement?

 

[Aqua Man]

The RQS statement still didn't really answer my question or maybe I'm not reading it right. It says that at night they use the energy they produced during the day to help further fuel growth. Ok...but what growth are they further fueling?

My understanding from that is that as they sleep they grow, maybe at not as high a rate but they grow. Is there something I'm missing from that statement?

First plants do NOT sleep they perform different processes and to correlate sleep with a plant drooping is just wrong.

Plants perdorm a multitude of processes depending on the presence or absence of light (and other factors but we are talking about light) Because the majority of the processes during light periodinvolve photosynthetic processes i would confidently assume that the plant is able to use less energy during the day because its focused on making energy.

At night this is not the case and it can then focus on using the stored energy made during the last light period for growth.

 

[Aqua Man]

Growth as in formation of new tissue etc

 

[Speedypete]

Ok bro so this topic is huge. What are you goals or what are you trying to understand? From there we can start and im sure the conversation will branch out alot because everything is kinda tied together.

First you want to go by the ppfd so you have an accurate idea of the light intensity… so first we need a way to measure that. To do that free a lix meter app will be good enough for your needs. I prefer the photone app and paid for the LED addon but thats not necessary. You will only really need this for one frow until you get the ppfd and distance measurements at the varying heights and intensity i can walk ya through all that no problem.

Then we can go over how to read the plants to determine gow happy they are with the current settings

I worked my way through understanding vpd. I have a good quality light meter now and ir temp. I find all this very interesting.Through reading i found different references to optimal leaf temp for photosynthesis. Some reference 82.4 degrees as optimal although varies strain to strain. Currently running 83 degrees with a leaf temp 79 degrees at 740-780 par

 

[Speedypete]

I worked my way through understanding vpd. I have a good quality light meter now and ir temp. I find all this very interesting.Through reading i found different references to optimal leaf temp for photosynthesis. Some reference 82.4 degrees as optimal although varies strain to strain. Currently running 83 degrees with a leaf temp 79 degrees at 740-780 par

Leaf Surface Temperature - The Overlooked Variable - Aelius LED

Do you know the temperature of your leaves? When growers convert to LEDs, it’s fairly common to use only a standard thermometer to evaluate if the space is

www.aeliusled.com

 

[Aqua Man]

I worked my way through understanding vpd. I have a good quality light meter now and ir temp. I find all this very interesting.Through reading i found different references to optimal leaf temp for photosynthesis. Some reference 82.4 degrees as optimal although varies strain to strain. Currently running 83 degrees with a leaf temp 79 degrees at 740-780 par

Thats air temps likely with co2 you can get away with a bit higher but optimal is around 77f many times even studies reference air temps instead of leaf temps.

Now genetics also plays a role because of where the plants originate and the climates they evolved in.

Hiw many hrs a day for light cycle?

 

[Aqua Man]

Leaf Surface Temperature - The Overlooked Variable - Aelius LED

Do you know the temperature of your leaves? When growers convert to LEDs, it’s fairly common to use only a standard thermometer to evaluate if the space is

www.aeliusled.com

Ok I haven’t read it all but i can cite you some studies if you like about leaf temp and ppfd… chandra did some great work in this area.

Im not saying they are wrong in all scenarios just that i prefer the actual sties rather than recaps because the studies also tell the variables and controls used

 

[Anthem275]

Thats air temps likely with co2 you can get away with a bit higher but optimal is around 77f many times even studies reference air temps instead of leaf temps.

Now genetics also plays a role because of where the plants originate and the climates they evolved in.

Hiw many hrs a day for light cycle?

I find a room temp of 81.5 to 82 to be about ideal even running co2

 

[Aqua Man]

I find a room temp of 81.5 to 82 to be about ideal even running co2

Exactly the same here bro

 

[Rootsruler]

I find a room temp of 81.5 to 82 to be about ideal even running co2

My air temps are very close to my leaf temps. Is this normal? Aquaman says 75* - 77* is where you want leaf temps. I realize each cultivar is a little different but do your leaf temps sit at around that temp or are they higher like your air temp?

Current conditions in the tent are 76*/55%. Leaf temps are 76*. Some of the new growth is coming in with 5 fingers so I'll let her run for another week and check new growth. They're getting to the point where I need to start LST so I'll see what comes of next week and decide what to do with them. I was thinking if they don't recover I might stick them in the little tent and flower and restart the big tent.

 

[Aqua Man]

My air temps are very close to my leaf temps. Is this normal? Aquaman says 75* - 77* is where you want leaf temps. I realize each cultivar is a little different but do your leaf temps sit at around that temp or are they higher like your air temp?

Current conditions in the tent are 76*/55%. Leaf temps are 76*. Some of the new growth is coming in with 5 fingers so I'll let her run for another week and check new growth. They're getting to the point where I need to start LST so I'll see what comes of next week and decide what to do with them. I was thinking if they don't recover I might stick them in the little tent and flower and restart the big tent.

All depends in light source, VPD, wind etc etc. can be the same, higher or even up to about 10f cooler…. Thats why an IR gun is soooo underrated for the cost

 

[Anthem275]

All depends in light source, VPD, wind etc etc. can be the same, higher or even up to about 10f cooler…. Thats why an IR gun is soooo underrated for the cost

I use a IR Temp gun as well. I have it handy at all times. For me 81,5 to 82 will produce correct leaf temps.

 

[Rootsruler]

New growth is 5 fingering. Tent environment sits at 79*/62%. Leaf temps are averaging 78*

Thanks @Aqua Man and @Anthem275!

 

[tobh]

ha, the IR gun comments. Dude, i bought one years ago and it won't die. I use it for soooo many things. Initially was for LST measurements, but then it became a dog toy, then for agar work, then for cooking, and working on cars, for teaching the kids thing on a whiteboard.... the utility of those things is endless and well worth the $15 or whatever they are now.

i'll give you five fingers @Rootsruler

 

[Observer]

ha, the IR gun comments. Dude, i bought one years ago and it won't die. I use it for soooo many things. Initially was for LST measurements, but then it became a dog toy, then for agar work, then for cooking, and working on cars, for teaching the kids thing on a whiteboard.... the utility of those things is endless and well worth the $15 or whatever they are now.

i'll give you five fingers @Rootsruler

Exactly how it went for me lol

Especially use it for cooking.