Interesting Paper On Vpd And Flushing

[SinCity]

Sure , you'll see a few post by me on there.
And I still don't flush.

Curious about what medium you use?

 

[Rootbound]

Something also to remember about water only method at the end of flower, are people using RO water or tap water? I am forced to use RO water to grow because my tap water is 1.3 ec... yuck!

 

[MidwestToker]

Curious about what medium you use?

Coco Coir and sometimes a mix of Ocean Forest and Pro-Mix HP for indoors.

 

[jumpincactus]

Sure , you'll see a few post by me on there.
And I still don't flush.

:D

 

[Glow]

I think you need to contextualise the parameters of the study and what was looked at with this one. Firstly, they were fertigating lightly in soil and they were using sufficiency range nutrients. Most hydroponic growers fertigate far more often and feed excessively within the luxury range to even excessive range. What would be the outcome of running water only in the last two weeks here? (Unknown because of the study's parameters). Also my own thoughts on this is something may be occurring at an organic (not inorganic) level where crop quality is concerned re the flush and this wasn't quantified through analysis. Certainly though once inorganic nutrients are in the plant tissue they cannot be flushed and that is bog standard plant science 101.

 

[FutureGrower]

Outside of the pettiness this Is a very interesting thread.

So I know chlorophyll will make your herb ash dark but I've ways been under the impression it's a mixture of the time ran, the cure, and the flush.

What does it mean when your herb smells and looks great but burns dark black without too much moisture? I had this once from a dispensary.

I tried smoking a unfinished bottom bud of my own stuff and just let it dry in air for 24 hours and it even ashed whitish grey. Actually kinda kicked my ass for about 10 minutes, was super racy like a bad haze despite it being a piney o.g., but didn't last long at all.l

But I grow in living soil and flushing is impossible. I don't even think about it but whenever I'm smoking others stuff I do.

Mostly because I dont understand much of the npk gardening though. I figure everything I put in my soil I could eat minus the agsil 16h I stopped using

 

[Glow]

Good article!

Supports what I have found in my own testing but doesn’t mention canabanoids production. Which I feel is also greater when nutrients are not withheld. Flavor is better too if fed properly pretty much to the end in my experience.

Umm yeah its actually a highly flawed article written by a guy who understands jack about plant science. So, for example, studies by renowned leaders in the field of cannabis research have shown that photosynthesis (I.e. cell division, carbon petitioning etc) dramatically slows shortly after the flowers reach near full size. In the last 10 - 14 days almost no to nil cell division is occurring. As a result the cannabis plant (note cannabis specific research) doesn't require nutrients during this period because nutrient requirement is determined by carbon petitioning and cell division. Writing a book on cannabis capitalism is one thing - understanding plant physiology is entirely another thing. I actually contacted this guy yonks back and sent him a link to the study (he asked the question and a scientist actually answered it for him). His response was, and I quote, "fuck you" lol.. This is not a guy you should be taking seriously where it comes to plant science because he clearly has no idea on the subject and is locked in his own ill formed views with a dogma that just makes him a science denialist.

 

[Glow]

Outside of the pettiness this Is a very interesting thread.

So I know chlorophyll will make your herb ash dark but I've ways been under the impression it's a mixture of the time ran, the cure, and the flush.

What does it mean when your herb smells and looks great but burns dark black without too much moisture? I had this once from a dispensary.

I tried smoking a unfinished bottom bud of my own stuff and just let it dry in air for 24 hours and it even ashed whitish grey. Actually kinda kicked my ass for about 10 minutes, was super racy like a bad haze despite it being a piney o.g., but didn't last long at all.l

But I grow in living soil and flushing is impossible. I don't even think about it but whenever I'm smoking others stuff I do.

Mostly because I dont understand much of the npk gardening though. I figure everything I put in my soil I could eat minus the agsil 16h I stopped using

If you are growing using very low nutrient levels I expect there is very little point in flushing although if you are adding nutrients simply stop supplying them 10 - 14 days out from harvest to achieve a similar thing.

 

[FutureGrower]

If you are growing using very low nutrient levels I expect there is very little point in flushing although if you are adding nutrients simply stop supplying them 10 - 14 days out from harvest to achieve a similar thing.

Yeah I feed once a cycle. Just a bunch of amendments top dressed theres no such thing as flushing in organics (labeled organic isn't really organic but I can respect if others disagree)

 

[MIMedGrower]

Umm yeah its actually a highly flawed article written by a guy who understands jack about plant science. So, for example, studies by renowned leaders in the field of cannabis research have shown the photosynthesis (I.e. cell division, carbon petitioning etc) dramatically slows shortly after the flowers reach near full size. In the last 10 - 14 days almost no to nil cell division is occurring. As a result the cannabis plant doesn't require nutrients during this period because nutrient requirement is determined by carbon petitioning and cell division. Writing a book on cannabis capitalism is one thing - understanding plant physiology is entirely another thing. I actually contacted this guy yonks back and sent him a link to the study (he asked the question and a scientist actually answered it for him). His response was, and I quote, "fuck you" lol.. This is not a guy you should be taking seriously where it comes to plant science because he clearly has no idea on the subject.

My results show some nutrients during the last 2 weeks makes a big difference.

Please post any info you are quoting. How does he know the plant is on its last 2 weeks? Its not like they will die if we dont harvest.

And what strain? They can grow very differently. I have 12-14 weekers than never stop growing and 9 weekers that are already ambering out.

Does he use pk boost? which ends the plants flowering prematurely in my opinion. What medium?, what envirenment parameters?

So many variables.

 

[Glow]

My results show some nutrients during the last 2 weeks makes a big difference.

Please post any info you are quoting. How does he know the plant is on its last 2 weeks? Its not like they will die if we dont harvest.

And what strain? They can grow very differently. I have 12-14 weekers than never stop growing and 9 weekers that are already ambering out.

Does he use pk boost? which ends the plants flowering prematurely in my opinion. What medium?, what envirenment parameters?

So many variables.

You may beginning to flush too early I expect if that is the case... Paper to read

Chandra, S. Lata, H , Khan, I. A. and Elsohly, M. A. (2008) Photosynthetic response of Cannabis sativa L. to variations in photosynthetic photon flux densities, temperature and CO2 conditions

Also see the research link at the beginning of this thread...

 

[Glow]

Yeah I feed once a cycle. Just a bunch of amendments top dressed theres no such thing as flushing in organics (labeled organic isn't really organic but I can respect if others disagree)

I really doubt there would be anything to be gained through "flushing" in your case. Again, it all comes down to the parameters/variables as to what can be gained. So because you are using organics and feeding within the sufficiency range that is very different from using high levels of inorganic nutrients as per a lot of hydroponic growing environments.

 

[FutureGrower]

I really doubt there would be anything to be gained through "flushing" in your case. Again, it all comes down to the parameters/variables as to what can be gained. So because you are using organics and feeding within the sufficiency range that is very different from using high levels of inorganic nutrients as per a lot of hydroponic growing environments.

Thanks man :)

 

[Glow]

My pleasure mate. I think the general consensus with a lot of people is that organically grown tastes better anyway. While I don't necessarily agree (e.g. all of our taste buds are completely different so how do you define good and bad tastes and all nutrients the plant ultimately uptakes, beside some amino acids, are ultimately inorganic whether you feed the plant organic or inorganic nutrients) but there could be some merit to this where it comes to improperly produced hydroponic cannabis.

 

[MIMedGrower]

You may beginning to flush too early I expect if that is the case... Paper to read

Chandra, S. Lata, H , Khan, I. A. and Elsohly, M. A. (2008) Photosynthetic response of Cannabis sativa L. to variations in photosynthetic photon flux densities, temperature and CO2 conditions

Also see the research link at the beginning of this thread...

I am saying flushing is not neccesary if plants are fed properly.

You are all over the place man. ;-)

 

[Glow]

Um nope I'm not. You asked for the research and I provided the research. And your point "I am saying flushing is not neccesary if plants are fed properly" has some merit albeit the point you made about I lose yield if I flush has no merit because that is an opinion which is disproven by scientific studies.

 

[FutureGrower]

My pleasure mate. I think the general consensus with a lot of people is that organically grown tastes better anyway. While I don't necessarily agree (e.g. all of our taste buds are completely different so how do you define good and bad tastes and all nutrients the plant ultimately uptakes, beside some amino acids, are ultimately inorganic whether you feed the plant organic or inorganic nutrients) but there could be some merit to this where it comes to improperly produced hydroponic cannabis.

I really enjoy the smoothness of my own stuff. I'm nowhere near dialed in and everything that I've harvested ashes perfectly, my raw papers screw with the look but in a pipe or bowl it burns super nice and clean. I over dried and cured without enough humidity as well as tons of other mistakes, but I did let them flower for a really long time(cannot remember off top, but I'm sure that helped alot with the smoothness.)

I haven't grown in nutrients side by side to say one way or the other. If I'm honest the reason I initially grew organically is because it's so easy, and now it's a hobby :)

 

[Glow]

The main thing is you are happy and if you are happy all is good because you grew it.

 

[FatManatee]

This study doesn't disprove the benefit of flushing.
Less then 10% of the plants composition, and only 10 different nutrients are presented in the statistics. The study did not inform about the amount of heavy metals or carbohydrates etc. found in the buds.

There is one important function in the plant when it goes 'fasting', called autophagy. The state of autophagy is achieved when healthy cells of a plant are robbed of heavily available nutrients. The plant will start to cannibalize itself, using up stored nutrients, followed by recycling other dead cells and even toxins like heavy metals, turning them into available nutrients for the plant to grow.

Flushing increases autophagy, and this is the reason why plants should be flushed

There's just way too many valuables missing in this study. Like the author said, some of the results should be ignored, because of his own mistakes. Feels like a study made by an inexperienced junior student.

 

[Ikkt]

You may beginning to flush too early I expect if that is the case... Paper to read

Chandra, S. Lata, H , Khan, I. A. and Elsohly, M. A. (2008) Photosynthetic response of Cannabis sativa L. to variations in photosynthetic photon flux densities, temperature and CO2 conditions

Also see the research link at the beginning of this thread...

Re read the paper and couldn't find anything about severely reduced or even stopped growth/photosynthesis in the last 10-14 days as you claim. The paper is interesting and well known but it's about a completely different matter or did I overlook what you're referring to?
The study from this thread and its finding that withholding nutrients in the last two weeks doesn't make a relevant difference doesn't tell us anything either, as they don't use a inert medium and as far as I read didn't quantify how much nutrients were still available from the medium. In Peat mixes and Coco it can be a lot, in correls or straight perlite I doubt the outcome would've been the same.
So I don't see any prove plants don't grow the last two weeks at all.
What are you specifically referring to?

Anyway, I think no matter what such a absolute statement is just wrong.
Cultivars that kind of never stop producing fresh bud are well known. On the other hand there are coltivars that are near death allready when trichomes aren't even mostly opaque.
That's just a very genetic dependent thing and thus there is no such absolute answer.


Two more thing concerning "Flushing", or whatever you choose to call it, were important for my change of mind many years ago:
Tobacco with dark ash and bad burn is normally a sign for _low_ mineral content of the Soil it's been growing in. Clean burning Tobacco normally comes from mineral rich soils, iirc it's especially Potassium (and Ca) content that is an important quality criteria and leads to a clean burn. Not totally sure though, read all studies I could find many years ago and dumped flushing completely after that.
There are more studies than you'll care to read about clean burning crops and I think what's true for Tobacco should work for us too.
Another thing that's a hint that flushing is nowhere near the most important thing considering a clean, tasty smoke is organic growing:
They often don't "flush", and even if they do, they won't get most cations out simply leaching with a little tap or ro water and more nutrient ions are constantly released from the organic fertilizer. Most only give water the last weeks without any leaching and nonetheless the myth sticks that organic (read: not flushed) weed would be much tastier. And that you don't need to flush with organics.
Doesn't really ad up this whole flushing thing, probably came from very badly grown rockwool commercial shit herb, grown like Tomatoes and oldschool commercial growers "knowledge".

As an anecdote, the only product I ever had that wasn't burning well and had black ash was excessively flushed and starved for four weeks and they were only good for hash and oil. Unsmokable.
That was the point I looked for studies on this topic, fund a lot and ditched any kind of flushing. I also started to make sure I give enough Ca and K till chop while everything else gets reduced cause I think it's what makes a good clean burn.
Think about molasses, has a lot K and Ca iirc. No wonder you can give a shit load of it till the end without problems, perhaps even benefits.